Full frame to crop technical comparison

[RPTDC]

Can someone explain if the following two scenarios would produce an essentially similar image or technically would one be better than the other?

Both cameras using the same aps-c lens.

Camera #1 a Sony a7cr obviously shooting in crop mode.

Camera #2 a Sony a6600.

The premise of the question is would the full frame camera in crop mode, which my understanding would reduce the megapixels to be similar to the aps-c camera's, create essentially the same result quality?

Thank you.

 

[Martin_99]

Can someone explain if the following two scenarios would produce an essentially similar image or technically would one be better than the other?

Both cameras using the same aps-c lens.

Camera #1 a Sony a7cr obviously shooting in crop mode.

Camera #2 a Sony a6600.

The premise of the question is would the full frame camera in crop mode, which my understanding would reduce the megapixels to be similar to the aps-c camera's, create essentially the same result quality?

Thank you.

Yes, image would be practically the same, just resolution will be slightly different:

A7cR crop - 26Mpx

A6600 - 24Mpx

After crop, image of A7cR will have all characteristics of apsc camera.

 

[John Crowe]

I agree. Until one buys longer lenses, or adds a 1.4x, if possible. Making use of the extra MP in the full frame sensor is hugely advantageous. Of course these longer lenses will be bigger, heavier, and more expensive, so it depends on how far one wants to go.

With my selection of lenses it is not often that I can beat my 50MP FF with my 32MP APS-C.

 

[RPTDC]

Thank you Martin. That's what I was thinking but didn't want to miss some factor.

I have both cameras. I keep the a6600 always under my car seat, making it available all the time. I would load up the A7CR for perceived "special photos" (ya!, they're all special. I'm definitely not a professional or need to be).

After taking the A7CR full frame with a Sony 20-70 FF lens and the 70 to 300 FF lens hiking in Canada this spring I determined this was too heavy and inconvenient for me in hiking activity.

Contemplating eliminating the full frame camera and lenses but keeping a6600 with perhaps sigma 18 - 50 or sigma 16 - 300.

 

[Bill Ferris]

APS-C crop mode effectively transforms a full frame camera into an APS-C system.

Assuming both cameras are being used from the same location in the same light to photograph the same subject using the same settings, then yes, putting the full frame camera in crop mode should result in a photo that's the same as the photo made with the APS-C camera.

 

[Bob]

You can go to Imaging-Resource.com and compare studio test photos yourself. Download the full frame image and resample down to ASP-C size for apples to apples.

(1) at high ISO the full frame clearly has less noise

(2) If you are using an APSC lens on both, then no different really, but if you want to compare full frame lens against the APSC lens, then you will see dramatic differences in depth of field.

(3) if you're ultimately viewing your photos on a phone, then no practical difference.

(4) if you're looking to keep your lens while upgrading the body to an a7, then I don't see the point at all.

 

[Mitchell Clark]

Lots of good responses in this thread, but I wanted to address something: you said

The premise of the question is would the full frame camera in crop mode, which my understanding would reduce the megapixels to be similar to the aps-c camera's

In practical terms, that's what's happening, but the lower megapixel count is actually just an effect. The cause is that, in APS-C mode, your camera is only sampling an APS-C-sized portion of the sensor. As such, it gathers less light than it would in full-frame mode since it reads from a smaller surface area. That's why the megapixel count is lower; there are fewer pixels in that region than there are in the whole sensor.

That may be a more useful way to think about it since it makes it a bit more obvious how the process actually works. If you have two cameras with different sensor sizes, but they use the same pixels, then yes, the image will be exactly the same if you cropped the larger sensor to use the same area as the smaller one.

 

[Keith Meinhold]

I just purchased an a7CR. My first time out with the camera, I took the raw files and was just dropped them into Lightroom. Looking at the images, I was dismayed to see that they didn’t look all that different from what I would’ve gotten out of my a6000! As it turns out, I had somehow put the camera in APSC mode without realizing it, and the reason why they looked so similar. Part of the reason I purchased the a7CR, is so that I can use my APSC lenses and still get 26 megapixels

 

[New Wrycuda]

Can someone explain if the following two scenarios would produce an essentially similar image or technically would one be better than the other?

Both cameras using the same aps-c lens.

Camera #1 a Sony a7cr obviously shooting in crop mode.

Camera #2 a Sony a6600.

The premise of the question is would the full frame camera in crop mode, which my understanding would reduce the megapixels to be similar to the aps-c camera's, create essentially the same result quality?

As a matter of interest, the well-regarded Nikon D7100 (DSLR) boasted an “1.3x extra crop mode” that changed the sensor area from 6000x4000 to 4800x3200, and they referred to this in terms of “image size”. (That’s actually a 1.25x crop, but they called it 1.3x to save an extra digit in the display… 6000/1.25 = 4800).

Most people preferred to crop manually rather than use 1.3x, but there were some minor advantages for metering and buffering.

For Sony, there’s a good argument for only using FF lenses for both formats.

 

[Bob A L]

Why would there be a difference in dof of a 50mm FF lens and a 50mm APS-C lens if both were used at the same aperture and in crop mode on a FF sensor camera as the OP was curious about?

 

[Dem Bell]

Why would there be a difference in dof of a 50mm FF lens and a 50mm APS-C lens if both were used at the same aperture and in crop mode on a FF sensor camera as the OP was curious about?

There wouldn't. For what the OP asked there is indeed no difference.

The scenario that Bob describes in his post is different from what the OP asked.

 

[RPTDC]

I just purchased an a7CR. My first time out with the camera, I took the raw files and was just dropped them into Lightroom. Looking at the images, I was dismayed to see that they didn’t look all that different from what I would’ve gotten out of my a6000! As it turns out, I had somehow put the camera in APSC mode without realizing it, and the reason why they looked so similar. Part of the reason I purchased the a7CR, is so that I can use my APSC lenses and still get 26 megapixels

Hmm.

Now Keith has me thinking. My original plan was to consider selling My A7CR and 20-70 Sony FF lens and keeping my "always in the car" a6600 which now has a sigma 18-50, with consideration of adding the new sigma 16-300.

Now I am considering keeping both cameras and FF lens. Keep the a6600 + sigma 18-50 under car seat always available. Add the sigma 18-300 to use hiking with either camera, making it a much lighter and more convenient (one lens along), yet have more than adequate photos for me with the APS-C or crop mode on the FF. I would then yet be able to utilize the A7CR full frame quality when I wish with the FF 20-70 and I have the Sony FF 24 mm prime 2.8.

Sorry to bore everyone with my "thinking out loud", but along with all your input it helps.

 

[Bob]

Why would there be a difference in dof of a 50mm FF lens and a 50mm APS-C lens if both were used at the same aperture and in crop mode on a FF sensor camera as the OP was curious about?

Because in order to get the same composition and framing, one would have to change the distance between the camera and the subject. That, in turn, changes the DOF (all else being the same).

For example, if a 50mm FF covers the head and torso, but only covers the head on an ASPC, then the photographer using the ASPC would have to step further back from the subject in order to get the same framing of the subject. Thus, the DOF is increased because DOF widens as we move further away from the subject.

 

[Bob]

Why would there be a difference in dof of a 50mm FF lens and a 50mm APS-C lens if both were used at the same aperture and in crop mode on a FF sensor camera as the OP was curious about?

There wouldn't. For what the OP asked there is indeed no difference.

The scenario that Bob describes in his post is different from what the OP asked.

Yes.

 

[Leonard Migliore]

Why would there be a difference in dof of a 50mm FF lens and a 50mm APS-C lens if both were used at the same aperture and in crop mode on a FF sensor camera as the OP was curious about?

Because in order to get the same composition and framing, one would have to change the distance between the camera and the subject. That, in turn, changes the DOF (all else being the same).

For example, if a 50mm FF covers the head and torso, but only covers the head on an ASPC, then the photographer using the ASPC would have to step further back from the subject in order to get the same framing of the subject. Thus, the DOF is increased because DOF widens as we move further away from the subject.

Both lenses have a focal length of 50mm. Both lenses are being used in crop mode at the same aperture. There will therefore be no difference in the images. In particulare, there will be no difference in the depth of field.

The focal lengths of APS-C lenses are actual; they are not given as equivalents. When I replaced my APS-C 35mm lens with a full-frame 35mm lens on the same camera (a D300), the framing was the same because the focal lengths were the same.

 

[New Wrycuda]

Why would there be a difference in dof of a 50mm FF lens and a 50mm APS-C lens if both were used at the same aperture and in crop mode on a FF sensor camera as the OP was curious about?

Because in order to get the same composition and framing, one would have to change the distance between the camera and the subject. That, in turn, changes the DOF (all else being the same).

For example, if a 50mm FF covers the head and torso, but only covers the head on an ASPC, then the photographer using the ASPC would have to step further back from the subject in order to get the same framing of the subject. Thus, the DOF is increased because DOF widens as we move further away from the subject.

Both lenses have a focal length of 50mm. Both lenses are being used in crop mode at the same aperture. There will therefore be no difference in the images. In particular, there will be no difference in the depth of field.

From the original post… “Both cameras using the same aps-c lens”.

The focal lengths of APS-C lenses are actual; they are not given as equivalents. When I replaced my APS-C 35mm lens with a full-frame 35mm lens on the same camera (a D300), the framing was the same because the focal lengths were the same.

There might be a slight resolution advantage in using a FF lens on an APS-C body since the central regions of the FF are likely to be better than the edges of an APS-C lens.

My son uses a S-Z FF 35mm f/2.8 lens on his APS-C Sony a5100, and the resolution is good across the field.

 

[MJ_Photo38]

very easy to respond to this, because if you look at modern Sony cameras, both their high res full frame bodies and APS-C bodies use theexact same sensor node with a 3.76µm pixel pitch.

The result being that the the APS-C and high res full frame sensors used by Sony have pixels of the exact same size, and subsequently the exact same noise, dynamic range on a pixel level, as well as having the same exact resolution if you use the full frame body in APS-C mode.

If you compare the A7RV to the A6700, you will realize that both cameras have the exact same pixels with the exact same performance.





The A7RV manages to extract about 1 stop more dynamic range due to capturing more light when using it in full frame mode, but in APS-C mode it's the exact same there too.





So if you question was "would an APS-C sensor that is about 26MP (the 24MP sensor used in the A6600 is very close to the 26MP sensor used in the A6700 when it comes to IQ) have similar image quality to a 61MP full frame sensor used in crop mode?", the answer is yes, and going further than that, the image itself will probably be the exact same.

--
(G.A.S. and collectionnite will get my skin one day)

 

[Bob]

Why would there be a difference in dof of a 50mm FF lens and a 50mm APS-C lens if both were used at the same aperture and in crop mode on a FF sensor camera as the OP was curious about?

Because in order to get the same composition and framing, one would have to change the distance between the camera and the subject. That, in turn, changes the DOF (all else being the same).

For example, if a 50mm FF covers the head and torso, but only covers the head on an ASPC, then the photographer using the ASPC would have to step further back from the subject in order to get the same framing of the subject. Thus, the DOF is increased because DOF widens as we move further away from the subject.

Both lenses have a focal length of 50mm. Both lenses are being used in crop mode at the same aperture. There will therefore be no difference in the images. In particulare, there will be no difference in the depth of field.

The focal lengths of APS-C lenses are actual; they are not given as equivalents. When I replaced my APS-C 35mm lens with a full-frame 35mm lens on the same camera (a D300), the framing was the same because the focal lengths were the same.

Yes, I agree. I mentioned that in bullet #2 of my original reply to the OP.

 

[UncleVanya]

For Sony, there’s a good argument for only using FF lenses for both formats.

? Why is that and what is the argument?

 

[New Wrycuda]

For Sony, there’s a good argument for only using FF lenses for both formats.

Why is that and what is the argument?

If you own both formats, using FF lenses means that you aren’t saddled with a bunch of APS-C lenses.