You and I both answered this question with respect to classic landscape
shots although Moose and Jeff responded with strong macro arguments.
Moose's argument that depth of field trumps diffraction limits for
several stops and Jeff's argument that small is beautiful do have to be
reckoned with for macro. But your argument about real lens resolution
has to be dealt with in both cases.
Chuck Norcutt
James King wrote:
> Chuck, I agree with you.
> I take many landscape shoots and insides of large rooms/temples etc.
> I made the decision that I had to go full frame when I went digital for
> two reasons,
>
> firstly all other things being equal the pixel pitch on a full frame
> camera is less than on a smaller sensor camera and so this puts less
> strain on the lens, by 22MP full frame only the best lenses run at
> optimal appetures are going to deliver 22MP of real resolution. If you
> look at the lens reviews on DP review many full frame lenses can do 22MP
> (just) smaller sensors can't deliver anything close to that with any
> lens in any situation because they put so much strain on the lens. You
> can see the clearly in the DP review graphs, regardless of if it is a
> dedicated crop leans or a full frame lens used on a crop camera. The
> limit is the lens resolution for non full frame by about 16MP. If you
> look at the non full frame graphs closely, if a lens is not very very
> good at f4 then the resolution does not usually improve much stopping
> down since diffraction is about to become a problem and by f8 the
> quality drops. This means that good non full frame lenses have to be
> very very good wide open especially if they are f4 to begin with, f5.6
> lenses on a non full frame are diffraction limited before you even stop
> down...
>
> Secondly I need wide and super wide angle, I have been to temples in
> china where there are 3 or 4 storey high Buddas inside a tower and there
> is simply no space to get much distance between camera and statue. In
> such cases a true 16mm just about gets it all in. Outside the temple the
> Olympus 24mm and 35mm shifts are used often and I need them to be 24mm
> and 35mm.
>
> If I was a street photography person (which I am not) or a portrate
> person I can see the 7D being attractive.
> Regards
> James
>
> On 06/08/2010 01:14, Chuck Norcutt wrote:
>> There might be perfectly fine reasons to get a 7D vs 5D Mk II but depth
>> of field for landscape shots will not be one of them. Although shorter
>> focal lengths lead to greater depth of field, the larger magnification
>> required from the smaller sensor leads to lesser depth of field.
>> Diffraction also places limits and tends to be the equalizer.
>>
>> On a 7D with its 18MP 1.6X sensor you are limited to an aperture of
>> approximately f/6.3 to maintain full resolution before diffraction sets
>> in. On a 5D Mk II with its 21MP full frame sensor you can use
>> approximately f/10 before diffraction starts rearing its head. If you
>> use a 15mm lens on a 7D at f/6.3 and a 24mm lens on a 5D Mk II at f/10
>> both have exactly (well, within rounding error) the same hyperfocal
>> distance of 5.7 feet and nearest focus of half that. Obviously, DOF for
>> other distances will be the same as well. Unless the 15mm lens on the
>> 7D is exceptional I think the advantage goes to the 5D Mk II. It's much
>> larger pixels mean the lens doesn't have to be as precise. But the
>> pixel density on even the 5D Mk II will be a challenge for lots of glass
>> and the 7D very much more so.
>>
>> I'm hoping for maybe a 5D Mk III which might have 7D-like features and
>> hope it doesn't have too many more pixels. But I wouldn't blame anyone
>> for getting a 7D. Smaller lenses would be a good benefit. :-)
>>
>> Chuck Norcutt
>>
>>
>> Moose wrote:
>>
>>> As I am usually working for the opposite of Dawid's shallow plane of
>>> focus, I've be wondering if a 7D might not be a better step for me
>>> than 5DII. The 15-85/3.5-5.6 (24-136 eq.) appears to be a very fine
>>> lens for it.
>>>
>>> Multi Mode Moose
>
>
>
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>
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