dtaylor said:Kernuak said:The biggest disadvantage I have found with the 7D, is softening at narrow apertures, due to the diffraction limited affects, resulting from the small pixel size. In fact, that was the reason I ended up getting the 5D MkII for my landscape work.
You don't need and shouldn't be using such narrow apertures on crop for landscape shots. Remember that for an identical FoV crop has 1.6x more DoF, so you don't need to stop down as much. In fact, for a given FoV and DoF diffraction does not impact any format more than the others. This is true for everything from 4/3rds to LF.
On any format it is beneficial to know and use hyperfocal distances. A typical 35mm shooter might choose f/16 for a landscape. A crop shooter might use f/11 in that instance. But a hyperfocal crop shooter might end up with f/8 or even f/5.6. He would get more and sharper fine detail than either of the other two yet still have sufficient DoF.
It's a very blanket statement to say that you shouldn't use such narrow apertures on crop cameras, it depends on the actual landscape, focal length and to a lesser degree the actual lens used. Also, hyperfocal distance isn't always appropriate to use. While I started paying more attention to hyperfocal distance when I got the 7D (and still do), if there is a cliff smack bang in front the lens about half a mile away, it's pretty pointless trying to get infinity focus at the expense of nearby detail. I also do some micro-landscapes, where hyperfocal focusing is completely useless and DoF is even more critical, plus there is generally more fine detail which is affected by softness. Also, f/11 on a 50mm lens wasn't always narrow enough to get sufficient DoF, even using hyperfocal focusing. Additionally, there are few modern lenses that have detailed enough distance scales to accurately judge the focal distance selected. You could argue that I could have chosen different subjects to make better use of the abilities of the 7D and I did for a while to experiment and try new things, but for rocky seascapes, the wide open landscape is the best option, which requires a lot of DoF, with a sharp detailed foreground.
Since getting the 5D, I find that I tend to frame differently, tending to go for a wider FoV, so essentially using the same focal length as on the 7D. As I am restricted to the same standing points (due to the high tidal range and inability to swim with gear on), the DoF is actually greater on the 5D than the 7D. Also, I still have the same options as with the 7D (albeit at a longer focal length), so I have greater flexibility.
I did once see some quoted DLA figures for different cameras and for the 7D I believe it was wider than f/5.6, so it doesn't take long to start seeing the effects of diffraction when shooting landscapes, if that is the case. While it isn't the whole story and acceptable sharpness is quite subjective (and less of an issue for landscapes to some degree), it is something to take into account. I'm not one to get hung up on so called scientific data (I have a scientific background), but the results I was getting spoke for themselves.
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