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.

 

[UncleVanya]

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.

The same can be said for any manufacturer who makes both apsc and ff and uses the same mount. Pentax and Nikon for example.
But counter arguments exist. It has been shown that flares outside the apsc image circle impacts apsc use of full frame lenses. It’s not a common issue but it does happen. Additionally, ff lenses can be larger and heavier than apsc lenses. They can also cost more. The wider lenses needed for apsc may have design challenges on ff making them much larger than apsc counterparts.
That said what I do is leverage both types of lenses on my apsc bodies. Dedicated apsc lenses for a few needs, ff reused for other needs. I own an a6600 and I have only two apsc e-mount lenses: Samyang 12mm/2 and Sony 20mm/2.8 (plus the wide converter). I have debated grabbing the Sigma 18-50/2.8 or the Sony 18-135 but so far I’ve resisted the urge. The E 20mm plus the FE 28-60 is a lightweight kit and works when I’m weight and size constrained.

 

[dsjtecserv]

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.

But your bullet #2 said there would be a difference in depth of field between an APSC lens and a full frame lens of the same focal length. That is incorrect. That is what several people have tried to point out.

Dave

 

[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?

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.

But my statement said when both were being used in crop mode on a FF sensor camera. Therefore no difference in distance required. A 50mm lens whether FF or crop design is a 50mm lens and either used on a crop sensor or FF in crop mode give the same field of view and dof.