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View Poll Results: Has the K-5 changed your perspective on Full Frame dSLRs?
I never wanted/needed a FF dSLR 17750.86%
I've changed my mind - I don't want/need a FF dSLR anymore 5916.95%
I've changed my mind - I want/need a FF dSLR now 82.30%
I've always wanted/needed a FF dSLR and still do 10429.89%
Voters: 348. You may not vote on this poll

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11-02-2010, 04:54 PM   #166
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QuoteOriginally posted by northcoastgreg Quote
This comes pretty close to my position. FF is, on the whole, better than APS-C; it's pointless to argue otherwise. But the question is whether the superiority is worth the cost. And here I don't mean just the cost of the camera (which is really not that significant any more), but the glass as well. High quality FF zoom glass costs more than the k-5. For many hobbyists (especially those with wives and families) the cost is prohibitive.
Actually, no, because truly equivalent lenses (I mean regarding FoV and DoF) are also quite equivalent in size/price.

For instance, take a 200/2.8 APS-C lens. Now take it's FF cousin, a 300/4.5... Quite the same price/size, if you have a look to current Canon/Nikon offerings.

Now take our good old FF 28-80/3.5-5.6... This would translate roughly into a 18-55/2-3.5, for all practical purposes such as FoV, DoF and noise (given that a FF sensor has a 1.5 stops advantage over APS-C).
Such a lens would cost quite a lot, no? More than these old kits ever went for...

And take a 70-200/2.8. There is no 50-135/1.8, isn't it? Again, this would cost so much I'd have to sell my whole family and some body parts to buy it.

So, no, APS-C has not really the edge on FF, regarding the price. It's just that it seems that way, but there is more than just the focal length...

11-02-2010, 05:28 PM   #167
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QuoteOriginally posted by dlacouture Quote
Actually, no, because truly equivalent lenses (I mean regarding FoV and DoF) are also quite equivalent in size/price.

For instance, take a 200/2.8 APS-C lens. Now take it's FF cousin, a 300/4.5... Quite the same price/size, if you have a look to current Canon/Nikon offerings.

Now take our good old FF 28-80/3.5-5.6... This would translate roughly into a 18-55/2-3.5, for all practical purposes such as FoV, DoF and noise (given that a FF sensor has a 1.5 stops advantage over APS-C).
Such a lens would cost quite a lot, no? More than these old kits ever went for...

And take a 70-200/2.8. There is no 50-135/1.8, isn't it? Again, this would cost so much I'd have to sell my whole family and some body parts to buy it.

So, no, APS-C has not really the edge on FF, regarding the price. It's just that it seems that way, but there is more than just the focal length...
The problem with this argument is two fold. First of all, most photographers (myself included) buy lenses based on angle of view, rather than on true equivalency. I am more pleased with a 50-135 f2.8 on crop, than I would be with a 70-200 f2.8 on a full frame camera. The second thing is that I struggle a lot more with getting enough depth of field. Shooting a 50 mm f1.4 lens on APS-C, I always stopped down to f2.8 minimum, just because I felt like I didn't have enough depth of field otherwise. On full frame I am going to end up shooting at f4 to get the equivalent depth of field.

I think a good discussion of equivalence is very enlightening (https://www.pentaxforums.com/forums/pentax-dslr-discussion/71896-low-noise-be...uals-zero.html). Basically, the full frame noise benefit comes down to having less depth of field. Otherwise, stopping down on full frame makes you lose the one stop benefit you think you have in high iso.
11-02-2010, 06:19 PM   #168
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Here's what I get from both playing around with the DOF clalculator, and conforms with some test shots I've done in the past on the film 35mm camera

For the same lens, same focal length, same aperture, the camera sitting at the same distance to the subject, the APS-C camera has shallower DOF than an FF camera.

OK, a Pentax APS-C camera has a 1.5x crop factor. To get the same Field-of-View with an FF camera, you either

a) Zoom in 1.5x with your zoom lens (assuming you still have the extra headroom)
or
b) You have to move to 1/1.5x the distance i.e. significantly nearer.

Or a combination of both

Now, with the Same FOV, same lens, same aperture, the DOF on the FF camera is now shallower than with the APS-C camera.

I'm too lazy to work through the mathematics, but most of this "shallower DOF" effect for the FF camera is simply because you have moved 33% nearer to the subject to get the same FOV.
or you have zoomed in 1.5x with your zoom lens.

Last edited by kittykat46; 11-02-2010 at 06:24 PM.
11-02-2010, 06:32 PM   #169
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please jump to post #89 https://www.pentaxforums.com/forums/1235952-post89.html

warning:
text not reacheable... (because of unconditional jump)

11-02-2010, 07:26 PM   #170
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they managed to make 16-18 megapixel APS-C's that perform awesome, now i hope they make 32-ish Megapixel FF sensors at consumer-reachable price levels!

There's just a bit more detail from longer focal length lenses on sensors with more megapixels.
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