FF body and lens vs APSC body and lens ISO performance

DocShaka said:

To summarize I'm understanding correctly - If we have FF camera on FF glass right next to APS-C camera on APS-C glass, same f-stop, same focal length (400 f5.6 on APSC and 600 f5.6 on FF - focal length would differ but f-stop would not, right?),

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A 600mm lens of any design is a 600mm focal length on any camera. A 400mm lens is a 400mm focal length on any camera. If you use a 600mm lens on a full-frame camera and a 400mm lens on an APS-C camera, both cameras will capture photos having the same angle of view. This is because of the relative crop factors - 1.0x for full-frame and 1.5x for most APS-C systems - not because they're the same focal length.

DocShaka said:

same shutter speed, then both cameras would automatically use the same ISO gain

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More directly to your concern over noise, in the same light, and at the same f-stop, and shutter speed, any two cameras of any format are working with the same exposure. As a result, the same ISO can be used by both cameras to produce images of the same lightness. However, if the two cameras are of different formats, the larger format camera should make a photo having less prominent noise.

When you mention, "ISO gain," it may not be what you think it is.

DocShaka said:

but inherently the FF sensor produces less noise at same ISO and therefore would be a cleaner image.

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More directly and accurately, the larger the sensor, less p prominent noise will be at the same exposure. In comparison with a smaller sensor camera, a larger sensor body will capture more total light at a given exposure. The visibility of noise in a photo is largely determined by the total light used to make the photo. Therefore, as sensor size increases while exposure settings stay constant, noise visibility in photographs will decrease.

DocShaka said:

Also the DOF would differ but not super worried about that in this comparison.

So I'm not seeing my ISO creep any higher with my setup than I would on a FF setup,

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Not if you're using the same f-stop and shutter speed with the APS-C camera as you'd be using with the full-frame camera. However, ISO isn't terribly critical. It's more an indicator of a good or weak exposure as opposed to a factor determining exposure.

DocShaka said:

but generally, the images will be a bit noisier. My camera isn't more starved for light with this setup.

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It depends. If you'd use a 600mm lens with a full-frame body, why not use a 600mm lens on the APS-C body? The 900mm equivalent angle of view would make it easier to fill the frame with your subject. Filling the frame, in turn, will result in less cropping which, in turn, translates to cleaner photos. In this scenario, the visibility of noise in the photos made with the APS-C body would be no worse than the noise in the photos made with the full-frame body, assuming they're made at the same exposure settings of f-stop and shutter speed.

If you'd opt for a shorter 400mm lens to have a more compact & lightweight kit, you'd enjoy the benefits of greater portability at the cost of about a stop of additional noise. If portability is a high priority, that may be a price you're willing to pay to get the system you want.

DocShaka said:

Did I get that?

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I suspect you may be associating ISO with noise to a greater degree than is merited. That said, if you understand that, whichever system you choose, options are available in lenses, focal lengths, and settings that will allow you to make quality images, you're in a good track and will eventually get the performance you desire.

Got it. Thank you so much for taking the time to clear all this up!

There is the concept of "equivalence" which can make your head spin to consider how all of the parameters interact.

In your situation using long lenses, you can achieve equivalence but you have to work at it. With an APS-C body you might be needing a 300mm lens, with a full frame camera you would be doing a similar thing with 450mm focal length. You might be able to get a 300mm f4 lens vs. a zoom containing 450mm that only has f5.6. Shooting with the f4 lens allows you to use lower ISO with the APS-C body for the same light conditions.

If you are trying to use the same lens with both bodies then it's not going to work as well.

DocShaka said:

FingerPainter said:

DocShaka said:

yerach said:

DocShaka said:

Hello all.

Im not terribly new to photography but I have a new perspective on the title and subsequently a question I was hoping you all might be able to answer.

I have shot Nikon for years, both FF and cropped but always on FF glass. A year ago I picked up a Fuji XT4 for something a little easier to travel with and honestly just like the tactility of the Fuji's.

Now I share my cameras with family members so I pretty much never see my Nikon stuff anymore and thought I would see what this xt4 could do for wildlife. I like to shoot birds in flight and landscape. So I picked up the 100-400 f2.8 and the x1.4 TC. I feel like I'm struggling so hard to get the ISO down. I have to shoot in what feels like much much brighter conditions... Like get out to shoot a couple hours earlier/later than I used to.

So basically the question is, if I had identical setups but one ApsC lens/camera, one FF lens/camera and a FF lens/APSC body, how would thier ISOs compare at the same given settings? Significant difference?

I'm just trying to decide if I stick to all Fuji (because the reach for the price is pretty good though AF leaves something to want and I'm guessing it's just not meant for wildlife) or do I stick to Nikon or even consider a switch to Sony?

Probably overcomplicating it but thanks for any info.

doc

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1. glass doesn't effect iso performance, all it can do is let you shoot at lower isos.

2. many ff sensors perform better than apsc, even superb apsc such as the fuji you mentioned, in high isos, if this is a major one to you, stick to ff.

3. currently the future is unfortunately not with Nikon, unless you've got the 5.5k$ to deal out for a z9, and even then, the glass, although sharper than anything else, is quite slow focusing, if you are to go ff, go Sony or Canon.

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Thanks for the reply.

1. Yes this is what I'm referring to. If I'm shooting with auto iso, overall shooting FF will keep that auto iso lower than the ApsC body & lens combo in same situations.

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If you use the same f-number and shutter speed on the FF and APS-C cameras, under the same lighting, the Auto-ISO systems should use the same ISO setting on both cameras. The result will be a noisier image on the APS-C camera.

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OK so this is what I was looking for.

To summarize I'm understanding correctly - If we have FF camera on FF glass right next to APS-C camera on APS-C glass, same f-stop, same focal length (400 f5.6 on APSC and 600 f5.6 on FF - focal length would differ but f-stop would not, right?), same shutter speed, then both cameras would automatically use the same ISO gain, but inherently the FF sensor produces less noise at same ISO and therefore would be a cleaner image. Also the DOF would differ but not super worried about that in this comparison.

So I'm not seeing my ISO creep any higher with my setup than I would on a FF setup, but generally, the images will be a bit noisier. My camera isn't more starved for light with this setup. Did I get that?

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If you have the same f/stop, same shutter speed, and same subject lighting, you should use the same ISO setting, independent of sensor size. However, this does not mean you will get the same results.

If you use the same focal length, your angle of view will vary with sensor size. If you are happy with your angle of view with a 100mm lens on a full frame, then you will be equally happy with a 50mm lens on a 2X crop body.

If you use the same f/stop, you results will vary with sensor size. Assuming the same angle of view, the same f/stop results in a deeper depth of field and less total light captured with a smaller sensor.

If you are happy with your depth of field at f/5.6 with your 100mm lens on your full frame, you will be equally happy with f/2.8 with a 50mm lens on a 2X crop body.

If you are happy with the noise in an image from your full frame camera with an ISO 800 exposure, you will be equally happy with the noise from a 2X crop body with an ISO 200 exposure. As it turns out, the lines up with the two stops you open up the crop body to match the depth of field of your full frame.

bjn70 said:

There is the concept of "equivalence" which can make your head spin to consider how all of the parameters interact.

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No need for spinning heads.

Same aperture diameter, same shutter speed, same angle of view and same subject will yield the same results, no matter what your sensor size.

bjn70 said:

In your situation using long lenses, you can achieve equivalence but you have to work at it. With an APS-C body you might be needing a 300mm lens, with a full frame camera you would be doing a similar thing with 450mm focal length. You might be able to get a 300mm f4 lens vs. a zoom containing 450mm that only has f5.6. Shooting with the f4 lens allows you to use lower ISO with the APS-C body for the same light conditions.

If you are trying to use the same lens with both bodies then it's not going to work as well.

Click to expand...

DocShaka said:

yerach said:

DocShaka said:

Hello all.

Im not terribly new to photography but I have a new perspective on the title and subsequently a question I was hoping you all might be able to answer.

I have shot Nikon for years, both FF and cropped but always on FF glass. A year ago I picked up a Fuji XT4 for something a little easier to travel with and honestly just like the tactility of the Fuji's.

Now I share my cameras with family members so I pretty much never see my Nikon stuff anymore and thought I would see what this xt4 could do for wildlife. I like to shoot birds in flight and landscape. So I picked up the 100-400 f2.8 and the x1.4 TC. I feel like I'm struggling so hard to get the ISO down. I have to shoot in what feels like much much brighter conditions... Like get out to shoot a couple hours earlier/later than I used to.

So basically the question is, if I had identical setups but one ApsC lens/camera, one FF lens/camera and a FF lens/APSC body, how would thier ISOs compare at the same given settings? Significant difference?

I'm just trying to decide if I stick to all Fuji (because the reach for the price is pretty good though AF leaves something to want and I'm guessing it's just not meant for wildlife) or do I stick to Nikon or even consider a switch to Sony?

Probably overcomplicating it but thanks for any info.

doc

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1. glass doesn't effect iso performance, all it can do is let you shoot at lower isos.

2. many ff sensors perform better than apsc, even superb apsc such as the fuji you mentioned, in high isos, if this is a major one to you, stick to ff.

3. currently the future is unfortunately not with Nikon, unless you've got the 5.5k$ to deal out for a z9, and even then, the glass, although sharper than anything else, is quite slow focusing, if you are to go ff, go Sony or Canon.

Click to expand...

Thanks for the reply.

1. Yes this is what I'm referring to. If I'm shooting with auto iso, overall shooting FF will keep that auto iso lower than the ApsC body & lens combo in same situations.

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simple solution, stop shooting auto iso...

DocShaka said:

2. I picked up the Z7ii before going all Fuji and was quite disturbed by the noise. I might be used to Fuji's easier-to-look-at noise but I wasn't having it for a $3k camera. I guess that's just the price of high pixel density?

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if you found z7ii footage noisy, i guess something is terribly wrong with your vision... (or your shooting...)

DocShaka said:

3. <\3 So I've been hearing. I'll never shoot Canon so Sony might be a real consideration.

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what black cat crossed between you and canon? there're not many as loyal as me to nikon, but when i saw need, i jumped to the boat that suited my needs best, the right choices aren't always the ones that feel best...

DocShaka said:

Got it. Thank you so much for taking the time to clear all this up!

Click to expand...

One simple fact to recall is that ISO is a concept that came from film, where different films could be manufactured with greater or lesser light sensitivity. A digital camera, in contrast, has only one sensor, with fixed properties. All changing the ISO does is tell the camera how light (or dark) you want the image to appear. It doesn't change the sensor at all, just what the camera does with the captured image. It would be entirely possible to throw out the idea of ISO completely for digital cameras, but it's a familiar idea to photographers and having the image appear immediately with the expected lightness is obviously very useful.

DocShaka said:

Hello all.

Im not terribly new to photography but I have a new perspective on the title and subsequently a question I was hoping you all might be able to answer.

I have shot Nikon for years, both FF and cropped but always on FF glass. A year ago I picked up a Fuji XT4 for something a little easier to travel with and honestly just like the tactility of the Fuji's.

Now I share my cameras with family members so I pretty much never see my Nikon stuff anymore and thought I would see what this xt4 could do for wildlife. I like to shoot birds in flight and landscape. So I picked up the 100-400 f2.8 and the x1.4 TC. I feel like I'm struggling so hard to get the ISO down. I have to shoot in what feels like much much brighter conditions... Like get out to shoot a couple hours earlier/later than I used to.

So basically the question is, if I had identical setups but one ApsC lens/camera, one FF lens/camera and a FF lens/APSC body, how would thier ISOs compare at the same given settings? Significant difference?

I'm just trying to decide if I stick to all Fuji (because the reach for the price is pretty good though AF leaves something to want and I'm guessing it's just not meant for wildlife) or do I stick to Nikon or even consider a switch to Sony?

Probably overcomplicating it but thanks for any info.

doc

Click to expand...

A much simpler take on things. Let's agree that a shot has been taken with both aps-c and FF in such a way to achieve the identical exposure settings and field of view. Take a step back and reverse the thinking. When we produce the final image the aps-c needs to be magnified more to attain the same size output. Just like film the more you enlarge it the more flaws come out, grain with film, noise with digital. This is where the FF advantage is. You magnify the noise less to get the size you want and there is where the FF advantage is visible. The larger you go the more apparent it is. Yes the exposure settings are the same but the total light due to sensor size wins in the end. You can't fight the physics of light

Dr_Love said:

DocShaka said:

...

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A much simpler take on things. Let's agree that a shot has been taken with both aps-c and FF in such a way to achieve the identical exposure settings and field of view. Take a step back and reverse the thinking. When we produce the final image the aps-c needs to be magnified more to attain the same size output. Just like film the more you enlarge it the more flaws come out, grain with film, noise with digital. This is where the FF advantage is. You magnify the noise less to get the size you want and there is where the FF advantage is visible. The larger you go the more apparent it is. Yes the exposure settings are the same but the total light due to sensor size wins in the end. You can't fight the physics of light

Click to expand...

The flaw with your reasoning is that you are thinking in terms of exposure (light per unit area), which is critical for film shooting, but not for digital. With digital, the important issue is total light captured. Therefore the better comparison is at the same total light captured, not the same exposure.

Unless you are shooting film, there is no need to shoot APS-C at the same exposure as full frame. As you correctly point out, doing so gets you different results.

A much better test is comparing the two formats at the same angle of view, same aperture diameter, same shutter speed, and same subject. This gets you the same results, independent of sensor size.

In order to make the math easy, let's compare a full frame with a 2X crop body.

If you are shooting the full frame with a 50mm lens at f/4 and 1/60 of a second, that's a 46° angle of view, and a 12.5mm aperture diameter.

With the 2X crop body, you would use a 25mm lens for that angle of view, and f/2 for that aperture diameter. You would keep the same 1/60 shutter.

Using a film based mindset, the crop body exposure is two stops higher. Using a digital mind set, the total light captured is the same.

Both will get you the same depth of field, same overall image noise, same perspective, etc.

.

Yes, you need more magnification (print to sensor size ratio) with the crop body, and magnification makes the noise more visible, but the crop body has more light per unit area, therefore it has less noise per unit area. The two balance each other out.

Magnification also makes any lens defects more visible, but you are only using the center portion of the lens, which is where lenses tend to be at their best. Depending on the lenses used, this could go either way. With today's modern lenses, the lens is seldom the limiting factor in image quality, so this may not be a concern.

.

The advantage of full frame is that you generally have the option of using larger aperture diameters. These larger diameters yield shallower depth of field, and let you capture more total light. If you can want very shallow depth of field, then the full frame has the advantage. Similarly, if you are in low light situations and can tolerate very shallow depth of field, the full fame has the advantage.

If you have ample light, the full frame can generally tolerate a higher amount of total light captured. This means that in these situations an image from a full frame will have less noise than one from a crop body. However, in these situations, a print from the crop body is likely to look noise free to the unaided human eye. Thus there may be little value in the even lower noise from a full frame.

That may be a convenient way to think about things but it isn't very accurate.

Member said:

A much simpler take on things. Let's agree that a shot has been taken with both aps-c and FF in such a way to achieve the identical exposure settings and field of view. Take a step back and reverse the thinking. When we produce the final image the aps-c needs to be magnified more

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In photography magnification has a particular meaning. This isn't it. You mean "enlarged".

Member said:

to attain the same size output. Just like film the more you enlarge it the more flaws come out, grain with film, noise with digital. This is where the FF advantage is. You magnify the noise less to get the size you want and there is where the FF advantage is visible.

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Not really. Yes more enlargement does show more problems, but the APS-C image is already noisier (that is to say, has a lower Signal to Noise Ratio = SNR) than the FF image before any enlargement has been performed on either. The reason is that the SNR depends primarily on how much light has been captured in the image. The FF sensor, having about 2.25 times the surface area has captured about 2.25 times as much light at the same exposure settings. Since the shot noise is the square root of the amount of light captured, the SNR of the FF image is about 1.5 times that of the APS-C image.

The Signal of the FF image is about 2.25 times that of the APS-C image because it captured about 2.25 times as much light,. The shot noise is about 1.5 times as much because 1.5 is the square toot of 2.25. The SNR is about 1.5 times as much because 2.25/1.5 is 1.5.

Member said:

The larger you go the more apparent it is.

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Well, it is true that the more you enlarge an image, the easier it is to see defects under the same viewing conditions (distance to displayed image, and visual acuity of the viewer) . That why looking at two images with two different pixel counts at the same % zoom will make the higher pixel count image look noisier when the two images actually had the same SNR.

However, if you make an APS-C image and a FF image with the same SNR, and display them both at the same size, and view them both from the same distance, they will look equally noisy, even though the APS-C image had to be enlarged more to reach that display size. That's because SNR of the whole mage indicates noisiness of the whole image.

To make an APC image with the same SNR as an FF image, it must have a higher exposure - about 2.25 times as high, or about 1 and 1/.6 stops higher.

Member said:

Yes the exposure settings are the same but the total light due to sensor size wins in the end. You can't fight the physics of light

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You're right about that, but enlargement doesn't change the amount of light captured in the image. Using a different size of sensor under the same exposure does change the amount of light captured.

FingerPainter said:

...

Not really. Yes more enlargement does show more problems, but the APS-C image is already noisier (that is to say, has a lower Signal to Noise Ratio = SNR) than the FF image before any enlargement has been performed on either. The reason is that the SNR depends primarily on how much light has been captured in the image. The FF sensor, having about 2.25 times the surface area has captured about 2.25 times as much light at the same exposure settings. Since the shot noise is the square root of the amount of light captured, the SNR of the FF image is about 1.5 times that of the APS-C image.

The Signal of the FF image is about 2.25 times that of the APS-C image because it captured about 2.25 times as much light,. The shot noise is about 1.5 times as much because 1.5 is the square toot of 2.25. The SNR is about 1.5 times as much because 2.25/1.5 is 1.5.

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Not really. At the same depth of field, same subject, and same shutter speed, the crop body and the full frame capture the same amount of light.

It's only when you insist on using a smaller aperture diameter for the crop body, that it captures less light.

Remember, the f/stop is the relationship between the aperture diameter and the focal length.

At a 46° angle of view, f/4 is a 12.5mm aperture diameter on a full frame, yet we would call that exact same aperture diameter f/2 on a 2X crop body.

Obviously, if you are going to use different aperture diameters with your comparison, you will get different results.

Unless you are shooting film, what is the advantage of using a different aperture diameter in order to maintain the same ratio of focal length to aperture diameter?

FingerPainter said:

FingerPainter said:

...

Click to expand...

FingerPainter said:

Yes the exposure settings are the same but the total light due to sensor size wins in the end. You can't fight the physics of light

Click to expand...

You're right about that, but enlargement doesn't change the amount of light captured in the image. Using a different size of sensor under the same exposure does change the amount of light captured.

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Insisting on using the same exposure for the comparison is like insisting on using the same focal length, and then complaining that the crop body doesn't give you as wide an angle of view.

Unless you are shooting film, you are better off using the same aperture diameter for the comparison, rather than increasing the noise and depth of field of the crop body by using a smaller aperture diameter.

Michael Fryd said:

FingerPainter said:

...

Not really. Yes more enlargement does show more problems, but the APS-C image is already noisier (that is to say, has a lower Signal to Noise Ratio = SNR) than the FF image before any enlargement has been performed on either. The reason is that the SNR depends primarily on how much light has been captured in the image. The FF sensor, having about 2.25 times the surface area has captured about 2.25 times as much light at the same exposure settings. Since the shot noise is the square root of the amount of light captured, the SNR of the FF image is about 1.5 times that of the APS-C image.

The Signal of the FF image is about 2.25 times that of the APS-C image because it captured about 2.25 times as much light,. The shot noise is about 1.5 times as much because 1.5 is the square toot of 2.25. The SNR is about 1.5 times as much because 2.25/1.5 is 1.5.

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Not really.

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Yes, really.

Michael Fryd said:

At the same depth of field, same subject, and same shutter speed,

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If you have the same DOF, same subject and same shutter speed, you cannot have the same exposure settings, yet I specified the same exposure settings, and same exposure settings is the premise of both the post to which I replied and of the OP.

Other than "not really", everything you say is true, but it requires that one ignore the premise given by OP and everybody else in this subthread.

Michael Fryd said:

...

Click to expand...

Dr_Love said:

DocShaka said:

Hello all.

Im not terribly new to photography but I have a new perspective on the title and subsequently a question I was hoping you all might be able to answer.

I have shot Nikon for years, both FF and cropped but always on FF glass. A year ago I picked up a Fuji XT4 for something a little easier to travel with and honestly just like the tactility of the Fuji's.

Now I share my cameras with family members so I pretty much never see my Nikon stuff anymore and thought I would see what this xt4 could do for wildlife. I like to shoot birds in flight and landscape. So I picked up the 100-400 f2.8 and the x1.4 TC. I feel like I'm struggling so hard to get the ISO down. I have to shoot in what feels like much much brighter conditions... Like get out to shoot a couple hours earlier/later than I used to.

So basically the question is, if I had identical setups but one ApsC lens/camera, one FF lens/camera and a FF lens/APSC body, how would thier ISOs compare at the same given settings? Significant difference?

I'm just trying to decide if I stick to all Fuji (because the reach for the price is pretty good though AF leaves something to want and I'm guessing it's just not meant for wildlife) or do I stick to Nikon or even consider a switch to Sony?

Probably overcomplicating it but thanks for any info.

doc

Click to expand...

A much simpler take on things. Let's agree that a shot has been taken with both aps-c and FF in such a way to achieve the identical exposure settings and field of view. Take a step back and reverse the thinking. When we produce the final image the aps-c needs to be magnified more to attain the same size output. Just like film the more you enlarge it the more flaws come out, grain with film, noise with digital. This is where the FF advantage is. You magnify the noise less to get the size you want and there is where the FF advantage is visible. The larger you go the more apparent it is. Yes the exposure settings are the same but the total light due to sensor size wins in the end. You can't fight the physics of light

Click to expand...

But what if the APS-C sensor has twice as many pixels as the FF sensor? Then you need to magnify the FF image more to get the size you want.

alfn said:

Dr_Love said:

DocShaka said:

Hello all.

Im not terribly new to photography but I have a new perspective on the title and subsequently a question I was hoping you all might be able to answer.

I have shot Nikon for years, both FF and cropped but always on FF glass. A year ago I picked up a Fuji XT4 for something a little easier to travel with and honestly just like the tactility of the Fuji's.

Now I share my cameras with family members so I pretty much never see my Nikon stuff anymore and thought I would see what this xt4 could do for wildlife. I like to shoot birds in flight and landscape. So I picked up the 100-400 f2.8 and the x1.4 TC. I feel like I'm struggling so hard to get the ISO down. I have to shoot in what feels like much much brighter conditions... Like get out to shoot a couple hours earlier/later than I used to.

So basically the question is, if I had identical setups but one ApsC lens/camera, one FF lens/camera and a FF lens/APSC body, how would thier ISOs compare at the same given settings? Significant difference?

I'm just trying to decide if I stick to all Fuji (because the reach for the price is pretty good though AF leaves something to want and I'm guessing it's just not meant for wildlife) or do I stick to Nikon or even consider a switch to Sony?

Probably overcomplicating it but thanks for any info.

doc

Click to expand...

A much simpler take on things. Let's agree that a shot has been taken with both aps-c and FF in such a way to achieve the identical exposure settings and field of view. Take a step back and reverse the thinking. When we produce the final image the aps-c needs to be magnified more to attain the same size output. Just like film the more you enlarge it the more flaws come out, grain with film, noise with digital. This is where the FF advantage is. You magnify the noise less to get the size you want and there is where the FF advantage is visible. The larger you go the more apparent it is. Yes the exposure settings are the same but the total light due to sensor size wins in the end. You can't fight the physics of light

Click to expand...

But what if the APS-C sensor has twice as many pixels as the FF sensor? Then you need to magnify the FF image more to get the size you want.

Click to expand...

It may have detail due to pixels but the FF still collects more light to begin with. Total light pretty much trumps all. Think it through, you need light for the pixels to do their job. If total light didn't matter then low light would always look as good as daylight.

FingerPainter said:

Michael Fryd said:

FingerPainter said:

...

Not really. Yes more enlargement does show more problems, but the APS-C image is already noisier (that is to say, has a lower Signal to Noise Ratio = SNR) than the FF image before any enlargement has been performed on either. The reason is that the SNR depends primarily on how much light has been captured in the image. The FF sensor, having about 2.25 times the surface area has captured about 2.25 times as much light at the same exposure settings. Since the shot noise is the square root of the amount of light captured, the SNR of the FF image is about 1.5 times that of the APS-C image.

The Signal of the FF image is about 2.25 times that of the APS-C image because it captured about 2.25 times as much light,. The shot noise is about 1.5 times as much because 1.5 is the square toot of 2.25. The SNR is about 1.5 times as much because 2.25/1.5 is 1.5.

Click to expand...

Not really.

Click to expand...

Yes, really.

FingerPainter said:

At the same depth of field, same subject, and same shutter speed,

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If you have the same DOF, same subject and same shutter speed, you cannot have the same exposure settings, yet I specified the same exposure settings, and same exposure settings is the premise of both the post to which I replied and of the OP.

Other than "not really", everything you say is true, but it requires that one ignore the premise given by OP and everybody else in this subthread.

FingerPainter said:

...

Click to expand...

Click to expand...

Yes, if you insist on using a smaller aperture for the crop body, you won't get the same results as the full frame. But that's true even if you are comparing two full frame bodies. If you use a smaller aperture for one full frame, you will get more depth of field and more noise than with the other full frame.

So we are back to asking why should we compare a crop body to a full frame using different aperture diameters and different amounts of total light? Such a comparison doesn't show the differences of the cameras, it merely shows that at smaller apertures you get deeper depth of field, and with less total light you get more noise.

Dr_Love said:

alfn said:

Dr_Love said:

DocShaka said:

Hello all.

Im not terribly new to photography but I have a new perspective on the title and subsequently a question I was hoping you all might be able to answer.

I have shot Nikon for years, both FF and cropped but always on FF glass. A year ago I picked up a Fuji XT4 for something a little easier to travel with and honestly just like the tactility of the Fuji's.

Now I share my cameras with family members so I pretty much never see my Nikon stuff anymore and thought I would see what this xt4 could do for wildlife. I like to shoot birds in flight and landscape. So I picked up the 100-400 f2.8 and the x1.4 TC. I feel like I'm struggling so hard to get the ISO down. I have to shoot in what feels like much much brighter conditions... Like get out to shoot a couple hours earlier/later than I used to.

So basically the question is, if I had identical setups but one ApsC lens/camera, one FF lens/camera and a FF lens/APSC body, how would thier ISOs compare at the same given settings? Significant difference?

I'm just trying to decide if I stick to all Fuji (because the reach for the price is pretty good though AF leaves something to want and I'm guessing it's just not meant for wildlife) or do I stick to Nikon or even consider a switch to Sony?

Probably overcomplicating it but thanks for any info.

doc

Click to expand...

A much simpler take on things. Let's agree that a shot has been taken with both aps-c and FF in such a way to achieve the identical exposure settings and field of view. Take a step back and reverse the thinking. When we produce the final image the aps-c needs to be magnified more to attain the same size output. Just like film the more you enlarge it the more flaws come out, grain with film, noise with digital. This is where the FF advantage is. You magnify the noise less to get the size you want and there is where the FF advantage is visible. The larger you go the more apparent it is. Yes the exposure settings are the same but the total light due to sensor size wins in the end. You can't fight the physics of light

Click to expand...

But what if the APS-C sensor has twice as many pixels as the FF sensor? Then you need to magnify the FF image more to get the size you want.

Click to expand...

It may have detail due to pixels

Click to expand...

And less visible noise due to less magnification. As you say: "You magnify the noise less to get the size you want and there is where the FF advantage is visible." (Unless the APS-C image requires less magnification.)

Member said:

but the FF still collects more light to begin with. Total light pretty much trumps all. Think it through, you need light for the pixels to do their job.

Click to expand...

And the exposure per unit area (and therefore noise per unit area) is identical, both statistically and visibly.

Member said:

If total light didn't matter then low light would always look as good as daylight.

Click to expand...

But low light always looks worse than high light no matter how much total light there is.

The simple fact is that (everything else being equal) large images have statistically less noise than small images but whether the noise is greater per unit area or more visible overall is a totally different matter altogether.

So called total light is irrelevant.

alfn said:

Dr_Love said:

alfn said:

Dr_Love said:

DocShaka said:

Hello all.

Im not terribly new to photography but I have a new perspective on the title and subsequently a question I was hoping you all might be able to answer.

I have shot Nikon for years, both FF and cropped but always on FF glass. A year ago I picked up a Fuji XT4 for something a little easier to travel with and honestly just like the tactility of the Fuji's.

Now I share my cameras with family members so I pretty much never see my Nikon stuff anymore and thought I would see what this xt4 could do for wildlife. I like to shoot birds in flight and landscape. So I picked up the 100-400 f2.8 and the x1.4 TC. I feel like I'm struggling so hard to get the ISO down. I have to shoot in what feels like much much brighter conditions... Like get out to shoot a couple hours earlier/later than I used to.

So basically the question is, if I had identical setups but one ApsC lens/camera, one FF lens/camera and a FF lens/APSC body, how would thier ISOs compare at the same given settings? Significant difference?

I'm just trying to decide if I stick to all Fuji (because the reach for the price is pretty good though AF leaves something to want and I'm guessing it's just not meant for wildlife) or do I stick to Nikon or even consider a switch to Sony?

Probably overcomplicating it but thanks for any info.

doc

Click to expand...

A much simpler take on things. Let's agree that a shot has been taken with both aps-c and FF in such a way to achieve the identical exposure settings and field of view. Take a step back and reverse the thinking. When we produce the final image the aps-c needs to be magnified more to attain the same size output. Just like film the more you enlarge it the more flaws come out, grain with film, noise with digital. This is where the FF advantage is. You magnify the noise less to get the size you want and there is where the FF advantage is visible. The larger you go the more apparent it is. Yes the exposure settings are the same but the total light due to sensor size wins in the end. You can't fight the physics of light

Click to expand...

But what if the APS-C sensor has twice as many pixels as the FF sensor? Then you need to magnify the FF image more to get the size you want.

Click to expand...

It may have detail due to pixels

Click to expand...

And less visible noise due to less magnification. As you say: "You magnify the noise less to get the size you want and there is where the FF advantage is visible." (Unless the APS-C image requires less magnification.)

alfn said:

but the FF still collects more light to begin with. Total light pretty much trumps all. Think it through, you need light for the pixels to do their job.

Click to expand...

And the exposure per unit area (and therefore noise per unit area) is identical, both statistically and visibly.

alfn said:

If total light didn't matter then low light would always look as good as daylight.

Click to expand...

But low light always looks worse than high light no matter how much total light there is.

Click to expand...

At the same depth of field, same angle of view, same shutter and same subject, the images from the full frame and the crop body will have the same amount of noise.

If you want to insist on comparing at different depth of fields, then the shallower depth of field will gather more light, and therefore the image will have less noise.

.

Think of a camera as a "black box". We have light coming in, and image data coming out.

What we care about is angle of view, depth of field, and motion blur. How the camera achieves a particular depth of field is an implementation detail.

It's silly to insist on comparing two different sensor sizes at the same exposure. That's like trying to find the fastest care by comparing them in the same gear at the same engine RPM. 2400 RPM in second gear will give different speeds on different cars. Knowing that speed doesn't tell you which car is faster.

alfn said:

The simple fact is that (everything else being equal) large images have statistically less noise than small images but whether the noise is greater per unit area or more visible overall is a totally different matter altogether.

Click to expand...

This depends on what you mean by "everything else being equal". I would say that they are equal when you have the same angle of view, same aperture diameter, and same shutter speed. Others might say, that instead of same angle of view, you should pick the same focal length. After all, if you like using a 50mm lens on your full frame camera, shouldn't "equal" mean we are comparing to an actual 50mm lens on every other camera?

Now you might say that we should consider the equivalent focal length. For instance if we are shooting our full frame at 50mm f/4, we should shoot our 2X crop body at 25mm (50mm effective). However, with a 25mm lens we need f/2 in order to keep the same aperture.

alfn said:

So called total light is irrelevant.

Click to expand...

alfn said:

But what if the APS-C sensor has twice as many pixels as the FF sensor?

Click to expand...

The amount of shot noise in a photo is proportional to the square root of the total light captured. Since shot noise is the predominant type of noise we see in most digital photos, that effectively renders factors such as pixel size, density, or total number irrelevant to discussions of noise in photos.

The benefits of a higher resolution sensor when applying post-exposure noise reduction, is another topic.

--
Bill Ferris Photography
Flagstaff, AZ
http://www.billferris.photoshelter.com

Bill Ferris said:

alfn said:

But what if the APS-C sensor has twice as many pixels as the FF sensor?

Click to expand...

The amount of shot noise in a photo is proportional to the square root of the total light captured.

Click to expand...

Statistically. Not in practice. Cut a print in half and it becomes twice as noisy statistically. Would you say it was a noisier print?

Bill Ferris said:

Since shot noise is the predominant type of noise we see in most digital photos, that effectively renders factors such as pixel size, density, or total number irrelevant to discussions of noise in photos.

The benefits of a higher resolution sensor when applying post-exposure noise reduction, is another topic.

Click to expand...

No, it isn't. It is the one and only topic I was addressing

Michael Fryd said:

alfn said:

Dr_Love said:

alfn said:

Dr_Love said:

DocShaka said:

Hello all.

Im not terribly new to photography but I have a new perspective on the title and subsequently a question I was hoping you all might be able to answer.

I have shot Nikon for years, both FF and cropped but always on FF glass. A year ago I picked up a Fuji XT4 for something a little easier to travel with and honestly just like the tactility of the Fuji's.

Now I share my cameras with family members so I pretty much never see my Nikon stuff anymore and thought I would see what this xt4 could do for wildlife. I like to shoot birds in flight and landscape. So I picked up the 100-400 f2.8 and the x1.4 TC. I feel like I'm struggling so hard to get the ISO down. I have to shoot in what feels like much much brighter conditions... Like get out to shoot a couple hours earlier/later than I used to.

So basically the question is, if I had identical setups but one ApsC lens/camera, one FF lens/camera and a FF lens/APSC body, how would thier ISOs compare at the same given settings? Significant difference?

I'm just trying to decide if I stick to all Fuji (because the reach for the price is pretty good though AF leaves something to want and I'm guessing it's just not meant for wildlife) or do I stick to Nikon or even consider a switch to Sony?

Probably overcomplicating it but thanks for any info.

doc

Click to expand...

A much simpler take on things. Let's agree that a shot has been taken with both aps-c and FF in such a way to achieve the identical exposure settings and field of view. Take a step back and reverse the thinking. When we produce the final image the aps-c needs to be magnified more to attain the same size output. Just like film the more you enlarge it the more flaws come out, grain with film, noise with digital. This is where the FF advantage is. You magnify the noise less to get the size you want and there is where the FF advantage is visible. The larger you go the more apparent it is. Yes the exposure settings are the same but the total light due to sensor size wins in the end. You can't fight the physics of light

Click to expand...

But what if the APS-C sensor has twice as many pixels as the FF sensor? Then you need to magnify the FF image more to get the size you want.

Click to expand...

It may have detail due to pixels

Click to expand...

And less visible noise due to less magnification. As you say: "You magnify the noise less to get the size you want and there is where the FF advantage is visible." (Unless the APS-C image requires less magnification.)

Michael Fryd said:

but the FF still collects more light to begin with. Total light pretty much trumps all. Think it through, you need light for the pixels to do their job.

Click to expand...

And the exposure per unit area (and therefore noise per unit area) is identical, both statistically and visibly.

Michael Fryd said:

If total light didn't matter then low light would always look as good as daylight.

Click to expand...

But low light always looks worse than high light no matter how much total light there is.

Click to expand...

At the same depth of field, same angle of view, same shutter and same subject, the images from the full frame and the crop body will have the same amount of noise.

If you want to insist on comparing at different depth of fields, then the shallower depth of field will gather more light, and therefore the image will have less noise.

.

Think of a camera as a "black box". We have light coming in, and image data coming out.

What we care about is angle of view, depth of field, and motion blur. How the camera achieves a particular depth of field is an implementation detail.

It's silly to insist on comparing two different sensor sizes at the same exposure. That's like trying to find the fastest care by comparing them in the same gear at the same engine RPM. 2400 RPM in second gear will give different speeds on different cars. Knowing that speed doesn't tell you which car is faster.

Michael Fryd said:

The simple fact is that (everything else being equal) large images have statistically less noise than small images but whether the noise is greater per unit area or more visible overall is a totally different matter altogether.

Click to expand...

This depends on what you mean by "everything else being equal". I would say that they are equal when you have the same angle of view, same aperture diameter, and same shutter speed. Others might say, that instead of same angle of view, you should pick the same focal length. After all, if you like using a 50mm lens on your full frame camera, shouldn't "equal" mean we are comparing to an actual 50mm lens on every other camera?

Now you might say that we should consider the equivalent focal length. For instance if we are shooting our full frame at 50mm f/4, we should shoot our 2X crop body at 25mm (50mm effective). However, with a 25mm lens we need f/2 in order to keep the same aperture.

Michael Fryd said:

So called total light is irrelevant.

Click to expand...

Click to expand...

I was replying, light-heartedly, to the post by Dr_Love. What you have posted here has no relevance to that conversation and does not address the point I was making.