Bench Marking Your DSLR

[sanking]

Loris,

I don't know what the real resolution of the A900 is, but I am pretty sure that it will not be nearly as high as the pixel count would indicate. In fact, I suspect that the theoretical maximum resolution is less than 70 lines per millimeter. And that will be for a sensor size of 24X36 mm.

With my MF Mamiyia 7II outfit I can put about 80-90 lines per millimeter on film quite easily with the 50mm and 65mm lens, assuming camera on a tripod and a scene that allows use of lens at aperture of f/16 or wider. My 80mm lens is not quite a capable, and about 70 lines per millimeter is about the best I can get with it. But regardless, actual picture size of the Mamiya 7 is 56X74 cm, about 2X that of full sensor DSLR in the long direction.

Bottom lines is that I have seen 30X40" color prints made from the Mamiya 7, drum scans, that a very experienced professional printer mistook for 8X10 work, so the capability of this camera for making very large color prints is not in doubt with folks who know it and recognize top quality.

Can the Sony A700 match Mamiya 7 in a color print at 30X40" size? If so, I will definitely be in the market. Having said that, there is always a comfort zone with film in that if you lose your digital file you can always do another scan so there is much less need for multiple back-up systems.

Sandy King

Tom sorry, I haven't noticed that you already mentioned 5D MkII. I agree, what I've read about A900 says that it outresolves many lenses; a crude calculation will reveal that you need a lens with resolving power of ca. 80lp/mm to match the resolution of A900's sensor -> that's a pretty serious figure, especially in the MF lens arena (where resolution tolerances are more relaxed due to less magnification ratio), also when considering Sandy's style too (landscapes, architectural w/ great DoF = high diaphragm figures = diffraction limited...). Maybe I'm wrong here -> just telling what I feel...

Regards,
Loris.

 

[Marco B]

Marco, the point was "if you want to reveal the true possibilities of a digital camera you have to shoot RAW", JPEGs are too much manipulated in-camera, to satisfy average Joe. Maybe you'd see more quality difference between Velvia and A900 if you had done it shooting RAW (that's why I wrote that; you say Velvia is very close, I say there could be some more difference when shooting RAW and doing fine post-processing)... To me even the A700 is better than 35mm ISO 400 B&W film using the same full frame lenses BTW.

Regards,
Loris.

Loris (and also Don),

The whole blablabla about JPEG in camera processing means nothing to me. Just like you both can not prove to me (as both of you are no Sony engineers) what/when/if the camera does any detrimental processing in the camera with JPEG output, I can't prove it doesn't either.

BUT....

I can have a look at the output! And that image just looks great!

PLEASE instead of babbling about some "would be" detrimental effect, tell or even better show (with a crop of the Alpha 900 downloadable image that I have so friendly made available) it is WHAT you don't like about this specific image / what is bad in the image (and forget about the JPEG thing, I just want to know what is not good enough: e.g. sharpness, resolved detail (and where), color????)

Is it just the mere fact that I wrote that it resolves 40 lp/mm, and not the expected 80 lp/mm? Well, than you have misread my lines, because, I also stated clearly that the test chart actually doesn't contain a higher resolution line pattern that could show more... and I wrote that there is still contrast left to resolve more. With which I meant the Alpha 900 in reality probably comes close to resolve the full 84 lp/mm, but that I just can't prove it because there is no such line pattern on the chart!

 

[Loris Medici]

Loris,
I don't know what the real resolution of the A900 is, but I am pretty sure that it will not be nearly as high as the pixel count would indicate. In fact, I suspect that the theoretical maximum resolution is less than 70 lines per millimeter. And that will be for a sensor size of 24X36 mm.

Actually, thinking again, the actual resolution limit could be well around 40lp/mm. There was a theorem that you need 2x sampling rate to guarantee a specific resolution.

With my MF Mamiyia 7II outfit I can put about 80-90 lines per millimeter on film quite easily with the 50mm and 65mm lens, assuming camera on a tripod and a scene that allows use of lens at aperture of f/16 or wider. My 80mm lens is not quite a capable, and about 70 lines per millimeter is about the best I can get with it. But regardless, actual picture size of the Mamiya 7 is 56X74 cm, about 2X that of full sensor DSLR in the long direction.

Indeed, on the other hand you have grain (= noise) with film, which will limit the resolution...

Bottom lines is that I have seen 30X40" color prints made from the Mamiya 7, drum scans, that a very experienced professional printer mistook for 8X10 work, so the capability of this camera for making very large color prints is not in doubt with folks who know it and recognize top quality.

Can the Sony A700 match Mamiya 7 in a color print at 30X40" size? If so, I will definitely be in the market...

I don't think so. Maybe A900 will give some nice results (with a different character) at that size but 30x40 isn't A700 bread for sure...

Regards,
Loris.

 

[Loris Medici]

Marco, what I said is what I said; no need to infer something else. You take it as is or you don't take it at all... On the other hand, this JPEG issue should mean something to you definitely, if you plan to do similar comparisons in the future...

 

[sanking]

Loris,

For sure the trade-off in digital/ film is nearly always spatial detail versus noise. If you don't print very large DSLR looks great, but over a certain size MF film will give better results.

Noise is not much of an issue with the films I generally use in MF, Fuji Acros and Portra 160 VC. A good scan of these films with a drum scanner, or with a high end flatbed with fluid mounting, should give a negative that could be easily enlarged up to 12X without grain/noise being an issue. On the other hand, getting a good scan requires a decent scanner and a competent operator.

Sandy King

 

[Marco B]

Guys, I invite you to download the images of the Alpha 900 and Velvia 100. If you have a printer that can print up to a size of 60x90 cm, than print it out that size. I am sure the Alpha 900 image (except for the horrible flash exposure), will give a fantastic result. I also think, except for non retouching and the need to sharpen it up a bit further, and possibly do some color correction, the Velvia 100 image will look great too in terms of detail, but slightly less than the Alpha 900.

A MF Velvia 100 scan of the same test chart would undoubtedly be fantastic as well, similar to the Alpha 900 and possibly even better at the 60x90 cm size, but I don't have such a scan available for you.... but the real advantage of the MF Velvia 100 scan would probably only show at even larger sizes, so over 60x90 cm...

 

[sanking]

OK, the loaner Canon EOS 5d, 12.8 mp, with 24-105 Canon zoom, that I plan to compare to my Fuji GA645Zi as a travel camera just arrived. I am looking forward to giving it a work out.

Initial thoughts. If this decision is based on size and weight the Fuji GA645Zi wins by a knock out at 15 seconds of the first round. It is by comparison tiny compared to the 5d with the 24-105 zoom.

Sandy

 

[Loris Medici]

...Initial thoughts. If this decision is based on size and weight the Fuji GA645Zi wins by a knock out at 15 seconds of the first round. It is by comparison tiny compared to the 5d with the 24-105 zoom.

Dear Sandy,

I can't think anything else than a Leica M8, in the digital realm (excluding the compact cameras), that can beat the GA645Z in terms of size and bulk...

Please share your opinion with us later, when you'll have evaluated the camera enough...

Regards,
Loris.

 

[monkeytumble]

Is there a B&W digital sensor camera? Or, could there be?

After reading about CCD optical sensors, Bayer filters, and demosaicing algorithms, I was left with the question is there a B&W digital sensor camera? I can't be the only guy who loves to shoot B&W and would appreciate a B&W camera... or, would folks like me just be too small of a niche to try to serve?

Jay Decker
Kennewick, WA

 

[sanking]

Hi Loris,

I will indeed share my opinion of the comparison, and probably post some image file comparisons as well.

Learning curve on these digital cameras is pretty steep, though. I am still trying to figure out how to do mirror lock-up because I don't want to disadvantage the 5d in resolution tests!!


Sandy

Dear Sandy,

I can't think anything else than a Leica M8, in the digital realm (excluding the compact cameras), that can beat the GA645Z in terms of size and bulk...

Please share your opinion with us later, when you'll have evaluated the camera enough...

Regards,
Loris.

 

[donbga]

After reading about CCD optical sensors, Bayer filters, and demosaicing algorithms, I was left with the question is there a B&W digital sensor camera? I can't be the only guy who loves to shoot B&W and would appreciate a B&W camera... or, would folks like me just be too small of a niche to try to serve?

Jay Decker
Kennewick, WA

Hi Jay Kodak produced a series of monochrome DSLR cameras. Read on here:

http://www.luminous-landscape.com/reviews/cameras/kodak-760m.shtml

Don Bryant