Crop modes on ff question

[Jaekae]

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similiar to a 35 mm lense or would it just be the same like taking a photo with the 28mm and cropping in post processing?

Like getting same wider angle distortion like the 28mm lense get without crop mode on. Or would the ”distortion” look more like the 35 without crop mode.

wondering because thinking to replace my 35 with a 28 but still want to sometime get the 35 look. But cant afford have both lenses

if anyone understand what i mean

 

[Mark S Abeln]

would it look similiar to a 35 mm lense or would it just be the same like taking a photo with the 28mm and cropping in post processing?

Crop mode crops the image, discarding pixels. In-camera crop should be largely the same as cropping after the fact.

Have you considered getting a zoom? Presumably you want a prime for the increased sharpness, but you are negating some of that advantage by cropping.

 

[FingerPainter]

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similar to a 35 mm lense

The angle of view would be very similar (you'd need a 1.25 crop mode to get the same angle of view, but depending on your camera, what is called a 1.2 crop may actually be a 1.25 crop). The sharpness would not look the same because your image would only have about 2/3 as many pixels. Your cropped image would also be noisier, because it would have been made with only about 2/3 as much light, (25/36 to be more precise).

or would it just be the same like taking a photo with the 28mm and cropping in post processing?

Yes, just like that.

Like getting same wider angle distortion

No such thing.

like the 28mm lense get without crop mode on. Or would the ”distortion” look more like the 35 without crop mode.

A 28mm lens, cropped, and a 35mm lens, shot from the same distance, give the same perspective, but so does an uncropped 28mm shot from the same distance.

wondering because thinking to replace my 35 with a 28 but still want to sometime get the 35 look. But cant afford have both lenses

Another potential solution is a zoom that covers both focal lengths

 

[Jaekae]

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similar to a 35 mm lense

The angle of view would be very similar (you'd need a 1.25 crop mode to get the same angle of view, but depending on your camera, what is called a 1.2 crop may actually be a 1.25 crop). The sharpness would not look the same because your image would only have about 2/3 as many pixels. Your cropped image would also be noisier, because it would have been made with only about 2/3 as much light, (25/36 to be more precise).

or would it just be the same like taking a photo with the 28mm and cropping in post processing?

Yes, just like that.

Like getting same wider angle distortion

No such thing.

like the 28mm lense get without crop mode on. Or would the ”distortion” look more like the 35 without crop mode.

A 28mm lens, cropped, and a 35mm lens, shot from the same distance, give the same perspective, but so does an uncropped 28mm shot from the same distance.

wondering because thinking to replace my 35 with a 28 but still want to sometime get the 35 look. But cant afford have both lenses

Another potential solution is a zoom that covers both focal lengths

aha so then even a 14 mm that look like alot of perspective distortion would look the same like a 35mm if i cropped it in post to the same field of view like a 35 would have?

if so i think it eould be ok to get that 28mm for me to have ”both” when use the 1,2 crop mode. Have 46 mpx so works ok with cropping. And it would be a 1.4 aperture 28 so it would still let in more light than getting a f4 zoom (2.8 zooms is to big imo)

 

[Bob]

Don't over think this. "Cropping" means trimming off the edges.

 

[bobn2]

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similiar to a 35 mm lense or would it just be the same like taking a photo with the 28mm and cropping in post processing?

yes it would look similar to the 35mm lens (no 'e' on the end) and yes it would be just the same as cropping in post processing. The key thing is the angle of view, and using the 35mm on full frame, or using a 28mmc and cropping by whatever method give the same angle of view.

Like getting same wider angle distortion like the 28mm lense get without crop mode on. Or would the ”distortion” look more like the 35 without crop mode.

This depends on what you mean by 'distortion'. Most likely you are talking about so-called 'perspective distortion', which depends on angle of view and subject distance. Given that a native 35mm and both methods of cropping result in the same AoV, this distortion is the same. Other distortions depend on the individual lens, so there is no rule.

wondering because thinking to replace my 35 with a 28 but still want to sometime get the 35 look. But cant afford have both lenses

if anyone understand what i mean

One of the advantages of big sensors and high pixel counts is that you can crop and still maintain high quality. A good workflow for people that don't have the happy talent of seeing and framing a shot at the time is to shoot with a wider lens and crop to a nice composition in post. Some people call it cheating, but it's just reverting to common practice in the days when people used film and enlargers.

--
Is it always wrong
for one to have the hots for
Comrade Kim Yo Jong?

 

[alfn]

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similar to a 35 mm lense

The angle of view would be very similar (you'd need a 1.25 crop mode to get the same angle of view, but depending on your camera, what is called a 1.2 crop may actually be a 1.25 crop). The sharpness would not look the same because your image would only have about 2/3 as many pixels. Your cropped image would also be noisier, because it would have been made with only about 2/3 as much light, (25/36 to be more precise).

So if I crop an 8 x 5 print down to 6 x 4 it becomes noisier? What form will that increase in noise take?

or would it just be the same like taking a photo with the 28mm and cropping in post processing?

Yes, just like that.

Like getting same wider angle distortion

No such thing.

like the 28mm lense get without crop mode on. Or would the ”distortion” look more like the 35 without crop mode.

A 28mm lens, cropped, and a 35mm lens, shot from the same distance, give the same perspective, but so does an uncropped 28mm shot from the same distance.

wondering because thinking to replace my 35 with a 28 but still want to sometime get the 35 look. But cant afford have both lenses

Another potential solution is a zoom that covers both focal lengths

 

[Bob]

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

also assuming that you do not move the camera either further or closer to the subject

would it look similiar to a 35 mm lense or would it just be the same like taking a photo with the 28mm and cropping in post processing?

Yes and yes. You’d be either cropping it in the camera or on your computer.

Thus, your image taken with the 28 would look like an image taken with a 35. However, because of the cropping, you’d have fewer pixels comprising the “35mm” shot.

Like getting same wider angle distortion like the 28mm lense get without crop mode on. Or would the ”distortion” look more like the 35 without crop mode.

wondering because thinking to replace my 35 with a 28 but still want to sometime get the 35 look. But cant afford have both lenses

You have four options. All four will produce the same result:

1. Print the shot taken with a 28mm and cut the edges off each side. You’d be discarding some printed pixels (i.e. ink dots)

2. Load the image into some editing software and crop it. You’d be discarding some pixels.

3. Put the camera in “crop mode” and let it crop for you. You’d be discarding some pixels.

4. Some cameras have an editing mode which let’s you crop an image afterwards. You’d be discarding some pixels.

if anyone understand what i mean

Real world tip:

Go with the 28mm and crop on your computer afterwards. You;ll have more flexibility regarding the composition. You’ll have less resolution that if you had just used a 35mm in the first place, but it will not be noticeable at all unless you’re printing on large paper.

 

[Leonard Migliore]

aha so then even a 14 mm that look like alot of perspective distortion would look the same like a 35mm if i cropped it in post to the same field of view like a 35 would have?

if so i think it eould be ok to get that 28mm for me to have ”both” when use the 1,2 crop mode. Have 46 mpx so works ok with cropping. And it would be a 1.4 aperture 28 so it would still let in more light than getting a f4 zoom (2.8 zooms is to big imo)

With 46 MP you can crop a lot before the image starts to suffer. And I don't know what brand of lens you're getting, but all the 28mm f/1.4 lenses I've heard of are very good so you will still retain sharpness.

I wouldn't bother with the 1.2 crop mode. Just shoot the full frame and crop it in your computer. You won't need a 35mm lens.

 

[FingerPainter]

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similar to a 35 mm lense

The angle of view would be very similar (you'd need a 1.25 crop mode to get the same angle of view, but depending on your camera, what is called a 1.2 crop may actually be a 1.25 crop). The sharpness would not look the same because your image would only have about 2/3 as many pixels. Your cropped image would also be noisier, because it would have been made with only about 2/3 as much light, (25/36 to be more precise).

So if I crop an 8 x 5 print down to 6 x 4 it becomes noisier? What form will that increase in noise take?

or would it just be the same like taking a photo with the 28mm and cropping in post processing?

Yes, just like that.

Like getting same wider angle distortion

No such thing.

like the 28mm lense get without crop mode on. Or would the ”distortion” look more like the 35 without crop mode.

A 28mm lens, cropped, and a 35mm lens, shot from the same distance, give the same perspective, but so does an uncropped 28mm shot from the same distance.

wondering because thinking to replace my 35 with a 28 but still want to sometime get the 35 look. But cant afford have both lenses

Another potential solution is a zoom that covers both focal lengths

 

[FingerPainter]

I accidentally hit "Post" on the preceding post before entering my reply. So here it is now;

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similar to a 35 mm lense

The angle of view would be very similar (you'd need a 1.25 crop mode to get the same angle of view, but depending on your camera, what is called a 1.2 crop may actually be a 1.25 crop). The sharpness would not look the same because your image would only have about 2/3 as many pixels. Your cropped image would also be noisier, because it would have been made with only about 2/3 as much light, (25/36 to be more precise).

So if I crop an 8 x 5 print down to 6 x 4 it becomes noisier?

No. If you crop an 8x5 print to 6x4, the 6x4 print will be nosier than the 8x5 print. The 9x 5 print didn't become noisier. The 6x4 part of the image didn't become any noisier either. That part of the image was already noisier than the whole 8x5 image.

What form will that increase in noise take?

Get two six-sided dice. Roll them and total the number of pips face up. Record the number, Repeat forty times. Calculate the standard deviation of the recorded values. Now discard the last sixteen numbers. Calculate the standard deviation of the first twenty-four. It will usually by greater. Note that none of the numbers changed during the process, yet the standard deviation of the smaller sample was larger.

Noise is variation in pixel values, and the value of pixels is subject to random variation because of the quantum nature of the generation of light. When you reduce the sample of pixels by cropping, the standard deviation of the remaining pixels is greater then the standard deviation of the whole uncropped image.

 

[Verkku]

I accidentally hit "Post" on the preceding post before entering my reply. So here it is now;

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similar to a 35 mm lense

The angle of view would be very similar (you'd need a 1.25 crop mode to get the same angle of view, but depending on your camera, what is called a 1.2 crop may actually be a 1.25 crop). The sharpness would not look the same because your image would only have about 2/3 as many pixels. Your cropped image would also be noisier, because it would have been made with only about 2/3 as much light, (25/36 to be more precise).

So if I crop an 8 x 5 print down to 6 x 4 it becomes noisier?

No. If you crop an 8x5 print to 6x4, the 6x4 print will be nosier than the 8x5 print. The 9x 5 print didn't become noisier. The 6x4 part of the image didn't become any noisier either. That part of the image was already noisier than the whole 8x5 image.

What form will that increase in noise take?

Get two six-sided dice. Roll them and total the number of pips face up. Record the number, Repeat forty times. Calculate the standard deviation of the recorded values. Now discard the last sixteen numbers. Calculate the standard deviation of the first twenty-four. It will usually by greater. Note that none of the numbers changed during the process, yet the standard deviation of the smaller sample was larger.

Noise is variation in pixel values, and the value of pixels is subject to random variation because of the quantum nature of the generation of light. When you reduce the sample of pixels by cropping, the standard deviation of the remaining pixels is greater then the standard deviation of the whole uncropped image.

thanks! That is a great explanition for noise, one of the best i have read.

 

[John Sheehy]

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similar to a 35 mm lense

The angle of view would be very similar (you'd need a 1.25 crop mode to get the same angle of view, but depending on your camera, what is called a 1.2 crop may actually be a 1.25 crop). The sharpness would not look the same because your image would only have about 2/3 as many pixels. Your cropped image would also be noisier, because it would have been made with only about 2/3 as much light, (25/36 to be more precise).

So if I crop an 8 x 5 print down to 6 x 4 it becomes noisier? What form will that increase in noise take?

This is a shell game of intended usage.

The resulting image is noisier, because the original impulses in the Z-axis are still there, but now they represent a larger percentage of the image area, each, but if you keep the image visibly small you won't notice, because of another factor: displayed image size. If you place the prints so that people are closer to the smaller image, then it will look noisier because the noise is more magnified. The noise impulses in the Z-axis do not get larger relative to any object in the original image, though, and it gets confusing if you don't make that distinction.

You might be tempted to visualize this analogy like a typical situation where noise is not a huge issue in an original print and is mainly subliminal, and subdued easily with processing. Everybody knows that noise can be that low, visually, so cropping and viewing a print closer does not reveal noise necessarily, but if you think of images that actually do have a lot of non-subliminal noise, then this magnification issue becomes more obvious.

The trimmed or cropped print analogy is used to show just how simple crop mode really is for the image, since many people think that it involves some kind of optical voodoo. If you want to think about the quality of results, though, you might consider using files fed to an image viewing program that stretches the image in each file to fit the screen. In that case, even with the same lighting, exposure, and ISO, crops will reveal more noise when the full image is already noisy-looking.

--

Beware of correct answers to wrong questions.
John

http://www.pbase.com/image/55384958.jpg

 

[Iliah Borg]

I accidentally hit "Post" on the preceding post before entering my reply. So here it is now;

If for example have a 28mm lense and a 35mm lense and put the 28mm on camera and start the 1,2 crop mode on my full frame camera.

would it look similar to a 35 mm lense

The angle of view would be very similar (you'd need a 1.25 crop mode to get the same angle of view, but depending on your camera, what is called a 1.2 crop may actually be a 1.25 crop). The sharpness would not look the same because your image would only have about 2/3 as many pixels. Your cropped image would also be noisier, because it would have been made with only about 2/3 as much light, (25/36 to be more precise).

So if I crop an 8 x 5 print down to 6 x 4 it becomes noisier?

No. If you crop an 8x5 print to 6x4, the 6x4 print will be nosier than the 8x5 print. The 9x 5 print didn't become noisier. The 6x4 part of the image didn't become any noisier either. That part of the image was already noisier than the whole 8x5 image.

What form will that increase in noise take?

Get two six-sided dice. Roll them and total the number of pips face up. Record the number, Repeat forty times. Calculate the standard deviation of the recorded values. Now discard the last sixteen numbers. Calculate the standard deviation of the first twenty-four. It will usually by greater. Note that none of the numbers changed during the process, yet the standard deviation of the smaller sample was larger.

Noise is variation in pixel values, and the value of pixels is subject to random variation because of the quantum nature of the generation of light. When you reduce the sample of pixels by cropping, the standard deviation of the remaining pixels is greater then the standard deviation of the whole uncropped image.

And one more thing: we tend to look at smaller prints closer

 

[John Sheehy]

Noise is variation in pixel values, and the value of pixels is subject to random variation because of the quantum nature of the generation of light. When you reduce the sample of pixels by cropping, the standard deviation of the remaining pixels is greater then the standard deviation of the whole uncropped image.

The image-normalized standard deviation increases. The absolute, raw standard deviation does not increase for any given exposure level, which is what some people may picture when "standard deviation" is mentioned. Most people quote standard deviations non-normalized, and it is usually metrics like DR or SNR that are normalized for a standard viewed image size.

 

[Mark S Abeln]

So if I crop an 8 x 5 print down to 6 x 4 it becomes noisier? What form will that increase in noise take?

Instead, think of taking a 16x20 print and cropping that down to 8x10, and then re-enlarging that crop to 16x20 again.

 

[John Sheehy]

So if I crop an 8 x 5 print down to 6 x 4 it becomes noisier? What form will that increase in noise take?

Instead, think of taking a 16x20 print and cropping that down to 8x10, and then re-enlarging that crop to 16x20 again.

The analogy of trimming a print is great for making it clear how simple a crop is (and lacking in any optical voodoo), but the analogy can kind of lose people regarding noise, I think, when they imagine real-world prints being cut, which does not give the impression of increased noise, partly because noise is smothered in most prints with processing.

Which is noisier; ISO 100 or ISO 50? Even though ISO 100 has more noise, neither is going to be considered noisy. That's what like finished images tend to appear, even at higher ISOs than 100; the noise is subliminal and irrelevant, and most prints won't look particularly noisier by trimming them and bringing them closer to your face. Noise just isn't registering perceptually as much as it exists in the underlying SNR spectrum. Take a very high ISO image and use the output of RawDigger, though, without NR and still pretty RAW except for demosaicing, tone curve, and white balance, and then it is more obvious. You can just take a noisy image of a flat, OOF wall and zoom in and out in an image viewer and see how magnifying a smaller part of the same wall more is noisier in the visible result.