"Robert Coe" <bob@1776.COM> wrote in message
news:bfflb49kbov8tm85boan6metohb1q293ki@4ax.com...
> : >> I have been looking on the net at photos taken with 24-70 2.8 lenses
> on
> : >> full frame bodies, but what I find strange is that the DOF @ f/2.8
> : >> doesn't look the same as it does on my primes @ f/1.8. Am I missing
> : >> something?
> :
> : > Yes. Try taking the same picture at f/2.8 with a prime and crop it to
> the
> : > same field of view as the zoom on the DSLR. The DOF should be the
> same.
> : > You will see that 50mm on a 35mm camera is not really equivalent to
> 38mm
> : > on a digital camera. It is still a 38mm lens; all you did was crop the
> : > edges off.
> :
> : Thanks for the reply, however I think that you have missed the point.
> It's
> : understandable though, as it's a bit full on and was expecting that it
> would
> : be mis-interpreted. In reality, it's a prime 'v' zoom comparison, with
> a
> : difference being different sensor sized bodies too.
> :
> : I am not interested in post process cropping in this post, as I do all
> my
> : cropping through the viewfinder. So if I want a big area of sky to put
> text
> : into, I judge this through the viewfinder. If I want a square image, I
> : judge this through the viewfinder, etc.
>
> It doesn't matter where you do your cropping. As CJ says, the DOF of a
> lens,
> for a given camera-to-subject distance, depends only on the lens's focal
> length and aperature.
>
> : Sometimes people look at cropped sensors, as just cropped sensors, but
> : forget that to frame the same image through the viewfinder with a bigger
> : sensor means that you have to get closer to the subject. This results
> in a
> : narrower DOF.
>
> But that's an entirely different matter. You said you've been looking at
> pictures on the net, not performing direct comparisons at measured
> distances.
> How do you know what the camera-to-subject distances were in those
> pictures?
>
> Bob
I think I will have to try a zoom and see how I get on with it. I guess
it's the only real way.
It would be good it I can get away with the 24-70, as it will mean I will
have 3 lenses in one. Less changing lenses, less cost, less weight, etc.
Still a bit skeptical on how it will compare to primes though. ;-)
>"Bruce" <no@nospam.net> wrote in message
>news:vhpnb4t2cvv1dvt4ihidi5d2ddjhjsgds7@4ax.com.. .
>
>>>I am looking to change to a full frame body. I have waited for long
>>>enough
>>>for the 5D replacement
>
>
>> Do you mean that you really cannot wait until Photokina, when the 5D
>> replacement(s) will be announced?
>>
>> http://photokina.en.koelnmesse.info/
>
>
>Mmm, I don't think it will though. Never say never though.
Wait until September 28 before you do anything rash. ;-)
Jake wrote:
>
> I think I will have to try a zoom and see how I get on with it. I guess
> it's the only real way.
>
> It would be good it I can get away with the 24-70, as it will mean I
> will have 3 lenses in one. Less changing lenses, less cost, less
> weight, etc. Still a bit skeptical on how it will compare to primes
> though. ;-)
The pro zooms are fantastic these days, the only thing is f/2.8 still
isn't f/1.2 <grin>. Actually there may be another thing confusing the
situation: fast lenses on DX actually show shallower DOF because they
are effectively 1.5x longer and longer means shallower DOF. I know you
explained and understand but in practice DX is better at shallow DOF
than FX unless you really need wide *and* fast. There is no Nikon 24mm
f/1.4, only 28mm f/1.4 AF and it's priced as a collector's item
(discontinued). There is a nice affordable old 28mm f/2 lens and 35mm
f/1.4, even a 35mm f/2 AF, all around $500-$800 maybe and very small.
The old 50mm f/1.2 is probably not as good as the Canon, the 1.4 should
be nice, I have the 1.2 & enjoy it. Works nice on the D700 I just picked
up but on DX it's like a 75mm f/1.2 which is more dramatic. For a really
exceptional 24mm lens the new tilt/shift one sounds great but expensive
and I believe it doesn't make all its movements on a D700 with the
flash/pentaprism thing getting in the way compared to the flash-less D3.
Re: Primes 'v' 2.8 Zoom 
Linear Mode
