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p.1 #9 · p.1 #9 · Digital Medium Format / 35mm equiv difference | |
I just think people don't want to open a really infected can of worms.... Sorry to see your post go "ignored".
There are ELECTRICAL differences, and there are OPTICAL differences. They both sort under the same principle, and that is "scale vs area". Most people seem to have a very hard time accepting this, but try to let go of preconceptions and just follow the general principles by which photography works... It's basically the same type of differences as when you compare µFT to FF/FX. And in general, your slightly mistyped (?) initial position is correct: Medium frequencies in the finished image get higher contrast the larger the base format is. This is because you (generally) use a higher F# to get the same image, and use less lp/mm on the sensor to get the same output resolution.
Which probably is why you haven't gotten any replies. Quite a lot of people tend to go into total and vicious denial if you mention that the smaller format is more dependent on having extremely sharp lenses, and that the smaller format also needs more light to get the same noise performance. Those that HAVE done the comparisons know this, but they also know that they'll get a full troll-clobbering if they say so.
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The easiest way to do a real comparison yourself (even if you only own one format!) is actually if you own a good constant aperture zoom. There are three (well.... maybe four...) possible real-world scenarios:
1) You have more light than you need, shutter speed is NOT a problem. Studio or sunlight conditions
2) You are light limited, and shutter speed limited. Sport or indoor conditions
3a) You are DoF limited, you want short DoF. Pure "I want to" conditions
3b) You are DoF limited, you need more DoF. Macro or landscape conditions
You can model all four with a zoom lens. Lets say you have a 70-200F2.8. Then the comparison cases (APS vs FF vs MF) would be for each of the four setups:
1) Use the same ISO for all images, then zoom in from 70/2.8 to 100/4.0 and then 135/5.6. Shoot in "A" mode, allow the exposure time to get longer as you zoom in.
2) Use the same exposure time for all images, and increase ISO as you stop down. Then shoot the same series, 70/2.8 to 100/4.0 and then 135/5.6.
3a) - basically the same as case 1)
3b) start from F8 in stead, that is 70/8.0, 100/11 and 135/16
Then crop out the EXACT frame that the 135mm setting images gave you from the 100mm and the 70mm shots - they will be smaller in pixels count of course. Then resize all shots to the same output size, and compare the results. The results might surprise you.
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You might want to try the "stupid" comparison too, constant aperture. Shoot at ISO3200, 70/5.6, 100/5.6, 135/5.6, same shutter speed for all three. Crop, scale and compare. Noise will be different, and DoF will also be different, but this is how most internet comparisons is done. It has no real meaning or purpose for practical photography, but people tend to do comparisons this way anyway.
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