Future of Pentax?

Started Mar 29, 2013 | Discussions thread
Gerry Winterbourne Forum Pro • Posts: 13,845
Re: Future of Pentax?

Andrew53 wrote:

BobORama wrote:

Frankly, your argument is nonsensical.  Other than changing the effective EFL, you don't get any more or less out of the lenses.

I disagree. I have been using full-frame for years. EFL is not the only difference. I have identified four differences of note.

EFL as you noted. This is generally negative for APS-C at the wide angle end where fast wide angle lenses are rare. I like the Sigma 8-16 but it is no replacement for my 16-35 f2.8.

Noise is about 1 stop better for a given framing and ISO. The K-5 is pretty good but one stop is one stop and it makes a difference if you like shooting a night.

DOF is not the same for a given f-stop. You need about a 1 stop wider aperture on APS-C to get the equivalent DOF of FF. So the f2.8 zooms of APS-C are more like the f4.0 zoom on full-frame. It is harder to get good background blur with APS-C than with FF for equivalent framing.

The lower enlargement requirement of larger sensors means the lens "defects" are also not enlarged as much. This is partially offset by the APS-C being able to use the "sweet" spot of a lens.

These differences extend to the Pentax 645D, where they are even more noticeable, so my hope is that Pentax not only releases a FF K-5 like camera, but I also hope they release an update to the 645D with a full 645 size sensor. These optical characteristics will always remain which is why the Nikon D800 is no replacement for a medium format. It isn't all about the pixels, noise or even sharpness. The "look" of larger formats has more to do with DOF and how it changes.

Indeed.  Where many people go wrong in comparing crop sensors with FF (or, indeed, any smaller with larger format) is confusing "is there a difference?" - to which the answer is always "yes" - with "is the difference worth the cost-size-weight penalty?" - to which the answer is "it depends on your priorities (which it's wrong to impose on others)".

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First camera 1953, first Pentax 1985, first DSLR 2006

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