Accurately comparing FF vs APS-C sensor performance? An open discussion.

Started Apr 8, 2013 | Discussions thread
OP VirtualMirage Veteran Member • Posts: 3,922
Re: Accurately comparing FF vs APS-C sensor performance? An open discussion.

Michael Fritzen wrote:


just thinking that one of the main problems in your comparison may be that you're trying to compare sensor sizes and their behaviour in the overall system of image taking. However this ends comparing camera models - an older A77 to a newer A99 with not only different sensor generations but also all the other processing and image taking tech. My feeling is that such a comparsion APS-C vs. FF would make more sense only if there were an A99 FF and an "A99c" with an APS-C sensor of the same generation, both in bodies with essentially the same processing tech and both released at the same time. If not, not only the evolution from one to the next sensor and camera generation plays an important role but also the model type with the 7-line generally showing some stripped down tech in comparison to the 9er models.

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Michael Fritzen

What does the generation of the sensor have to do with it?  That isn't the point, just an observational aide in my comparison for such a scenario.

If you wanted to compare a more current generation sensor, then I could have thrown in the D7100.  But then people would spout out about the inconsistency of comparing an OVF DSLR with and EVF SLT and the slight disadvantage an SLT has.  But it would be a more modern sensor

SNR 18% (dB, Screen/Print):

  • ISO 400: 31.6 / 36.5
  • ISO 1600: 25.7 / 30.5


  • ISO 1000: 29.5 / 34.3
  • ISO 4000: 23.5 / 28.3

Difference: 2.1-2.2 / 2.2 in favor of the D7100

Dynamic Range (EV, Screen/Print):

  • ISO 400: 11.8 / 12.6
  • ISO 1600: 9.9 / 10.7


  • ISO 1000: 10.5 / 11.3
  • ISO 4000: 8.5 / 9.3

Difference: 1.3-1.4 / 1.3-1.4 in favor of the D7100

Tonal Range (bits, Screen/Print):

  • ISO 400: 7.4 / 8.2
  • ISO 1600: 6.5 / 7.3


  • ISO 1000: 7.1 / 7.9
  • ISO 4000: 6.1 / 6.9

Difference: .3-.4 / .3-.4 in favor of the D7100

Color Sensitivity (bits, Screen/Print):

  • ISO 400: 19.8 / 22.2
  • ISO 1600: 16.6 / 19.0


  • ISO 1000: 18.5 / 20.9
  • ISO 4000: 14.9 / 17.3

Difference: 1.3-1.7 / 1.3-1.7 in favor of the D7100

But I imagine this comparison will have more crying foul.  But it is probably closer to what you were mentioning when it comes to the generation gap, at least the perceived generation gap.

As for the A77 and A99, they were probably developed closer together in the development timeline that the A99 and D7100.  The point wasn't to compare camera technology itself and how far one may have progressed over another.  It was just to show potential amount of loss in advantage one has over the other in a particular situation as I described, nothing more.

The Full Frame still has numerous advantages and situations it can fill that the APS-C cannot achieve, or at least not yet to the level of competency a Full Frame can provide.  This wasn't a smear campaign to try and put the Full Frame in the negative light, its just an observation of what I feel is a very real situation that I can see myself running into.  At worst, it wouldn't be any lower in quality than my A77 I am happy with.  But in majority of the other situations, it will be superior.  This I have already mentioned.

But I feel others are not quite grasping that and think this is a direct comparison of the A99 and A77, when in reality they were just used as examples for two different sensor sizes.  I could have labeled as "Camera A" and "Camera B" to explain my observation, but I felt people wouldn't be interested in fake camera names and scores that no longer hold a meaning.  I could have even used Nikon or Canon cameras, but I am a Sony user talking in a Sony forum.  So I felt best to use Sony cameras.

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