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 p.6 #2 · Voigtländer 50mm f2 apo VS Zeiss Loxia 50mm f2 | |
graytrekker wrote:
Alan:
I am not picking on anyone here - just trying to understand what people are talking about.
I have noticed that on the last few threads you have started, people sometimes make statements about lenses - "rendering", "sharpness", etc. You always ask them to post a photo of what they are describing so we can all be informed and understand what the poster is trying to get across. That would certainly be useful. Yet, I don't think I have seen anyone do that yet, which is a shame as I would also like to be clear on what they are describing, or why one would think think something supposedly so important about lens characteristics.
I am a scientist (not a troll) and like to see the data. Please post examples people!
Thanks
Doug...Show more →
I think part of the issue is, as shown in the next response to your post, is that there even doesn't seem to be a single definition of microcontrast.
Is it simply the higher lpm used in MTF values, but which is "micro" enough: 30, 40, 50... ? Zeiss lenses are praised for their micro-contrast but latest GMs seem to score higher on that front...
Or is it some less obvious quality like "color tonality gradation", then it's really strange that nobody tests this. I think if you break down the color space to some basic values (e.g. RGB) it should be possible to measure the "color resolution" (+ "aberrations" like color cast) this way...
And with rendering it's even worse, as in the most broad meaning it's just how the whole picture looks. So, everything from resolution through colors and bokeh to aberrations (CA, coma, vignetting, ...). But then, it's also very often used to describe specifically bokeh, maybe because the differences are often very visible there (esp. when viewing at 100%).
Anyways, to start ending this rant, I think it's difficult to show those differences in "rendering", because viewing the whole image is very subjective (some people will prefer warmer colors, less contrast, ...) and breaking it down into different factors, while maintaining some "cohesion", is difficult.
As for examples, I think Fred's tests are the most complete we have. He shows both bokeh rendering and infinity shots when checking center/midframe/corner resolution + some general sample shots. While I'd like to see sample pictures from people who claim one lens "renders" better than the other, I also understand it takes a considerate effort to actually do a meaningful comparison and most of us are not walking with 2 cameras mounted with 2 similar lenses just to compare them...
It's an interesting topic for myself too, as recently I've been wondering what I would actually gain from moving from 17-50/4 to 16-35/2.8 (apart from the obvious: 2.8 and 1mm wide  ), as in the end I'm not interesting in pixel peeing but viewing the picture as a whole at moderate sizes (let's limit this to monitors + large tvs on the extreme end).
The same way I'm trying to find out why I can often pick out (favorably) photos taken with Samyang 85/1.4AF, when on technical level Sigma 85/1.4DN beats it in every category (well, except distortion but that is corrected by a profile with enough resolution to spare).
I also wanted to do a quick & dirty comparison between 17-50/4 and 14-24/2.8DN I have, which would also fall under this "rendering" discussion I guess, but the weather was too "dynamic" today for me to take similar enough shots...
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. I'm thinking good in more ways than bad. I have the lens, and would never shoot landscape at F2 with it. 