Hi Bill,
Good comments make for a good discussion, always appreciated.
I am aware of the suggestion by Ctein that 4/3 is good enough for A2-size prints. I never had 4/3, but for a long time I was using APS-C. Many of my best images were shot on 12 MP APS-C and those images make for beautiful A2-size prints.
But more is always better, isn't it? Getting myself a full frame camera at 24 MP resulted in a few experiments comparing A2-size prints from 12 MP APS-C and 24 MP full frame. Mostly the 24 MP full frame had a visible but not very obvious advantage but in one case I could not tell those A2-prints apart, regardless viewing distance.
Getting onto 39 MP MFD and comparing with 24 MP full frame the MFD system had a clear resolution advantage when pixel peeping on screen, using due scaling, but A2 prints were very close. With my vision, a loupe was needed to tell them apart. The differences were readily visible with the loupe, so detail was correctly transferred to print.
Printing at A1 the MFD has shown advantage.
With the A7rII I have now, the 42 MP A7rII is a good match for the 39 MP MFD. It is actually more up to the lenses. In the short end the three Zeiss Distagons I have owned would be no match for the excellent Canon 16-35/4L but the Sonnars would outperform all my long zooms, except the old 80-200/2.8 G APO.
But again, I made a crop representing A0 comparing the Canon 16-35/4L at 24 mm with the Distagon 40/4 CF FLE, the print was as merciless showing the weakness of the Distagon as pixel peeping on screen. That is the print was merciless when viewed close, say at 50 cm or. Moving back to say 100 cm the MFD image was a bit better. At 50 cm viewing distance it was not really acceptable in the area that was weak. I guess the MFD image delivered a bit higher MTF at low frequencies but lacked high frequency detail.
My take is that present 24x36 mm goes a long way regarding image quality when paired with very good or excellent lenses.
Personally, I prefer zooms, so I am not really into high quality single focals. Lenses like the Otuses would stretch 24x36 mm even a bit farther.
So, my take is that 24x36 is certainly good for a good bit beyond A2-size and probably be able to deliver good quality on A0.
But, a well designed MFD system in proper hands would outperform a 24x36 mm system. No doubt about that. The new 'G-format' systems use Sony sensors and I would guess that those sensors will be replaced by newer versions keeping up with Sony's smaller sensor designs.
One thing to keep in mind is that the X1D and GFX are priced just a bit higher than some high end 24x36 system, like Nikon D5, Canon 1DXII and foremost red dotted cameras and all the most expensive 24x36 mm systems have relatively low pixel counts. The 'pro' Canons and Nikons are built for speed. Regarding Leica, ask the red dot forums…
My impression is that the X1D lenses are priced a bit below Otus pricing. They obviously don't have f/1.4 or even f/2 apertures and they may or may not have fully corrected axial chroma…
Anyway, I think that you can get a lot of excellent image quality from those systems at prices you could very well spend on 24x36 mm, too. Especially the red dotted ones. If that image quality is needed or not is a different question but it is a worthwhile question.
Best regards
Erik
As a side note, I have a lot of red dots on my Sony A7rII, I bought a bunch of them from Avery for around 2$. On the A7II I have green dots. Just to be able to tell them apart.
Eric, I find your post well reasoned and I essentially agree with your assertions. However, I have a couple of comments to make.
Other factors remaining constant, the number of photons captured is proportional to the sensor area. Since the SNR is proportional to the square root of captured photo-electrons, the factor of 1.6x improves the SNR by only a factor of 1.26. This factor of 1.6 is considerably less than the difference between full frame 135 (24 x 36 mm) and APS (15.7 * 23.5 mm), where the factor is 2.34, resulting in a SNR factor of 1.53.
Sweet spot is rather subjective, and depends on ones needs and preferences. No less an authority of Ctein stated in an interview with Michael that he considered MTF (micro four thirds) to be a sweet spot, meeting his image quality needs for prints up to A2. As the technology of sensors (film and digital) has advanced, the trend has been to move to smaller sensors for portability and convenience.
Same for me. I don't currently print beyond A2 and my Nikon D800e meets my needs, but I might upgrade to the D820 or whatever the D800e successor will be called in order to get electronic first shutter and other improvements.
Regards,
Bill
