How can the Pentax 40/2,8 be so small?

Griffin

Griffin

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And why don't they make more lenses this way? Is it related to the focal length and image circle? Are there any drawbacks on this design? I'm just curious.
 
the Voigtlander Ultron 40mm and the Canon 40mm are pancake lens also. I do not know exactly why but it certainly seems to be something about the 40mm focal length that lends itself to compact or pancake lens style.
 
I've read time and again that the Pentax 40 2.8 isnt a great performer, that these days it's markedly overpriced, and I already have the outstanding Konica Hexanon 40 1.8, but none of this seems to dampen just how much I'd like to have a play with the astonishingly small Pentax one
 
Even the standard 50mms you us to get for oly, Pentax etc.. were small, and fast, and good quality, these days, lenses tend to be much bigger, I think this is part AF systems, but more because people want a 'pro' look, either for ego reasons, or because clients expect a 'pro' look.
If someone showed up to my wedding with a Minolta tc1, it might just not look the part...
 
i have the 40mm Pentax lens. It is actually too small! Mine the film version, not auto focus or anything..Maybe they are all same? I own a Nikkor 45mm GN lens which is pretty small but focuses the wrong way! The Nikkor is both sharper, better flare control and easier to use. Busy with a Minolta 45mm. Much larger but bigger aperture, f2.
A Pentax ME/MX with the 40mm is a very compact unit.
 
For an SLR designed lens, the Pentax 40/2.8 is really small, though it includes AF.
I cannot believe that a 40mm FF prime lens (up to f2.5) for any SLR or mirrorless mount has to be essentially bigger. It could be even smaller for APS-C or 4/3 sensors. Shouldn't it?
 
Obviously most people dont care a lot about size in SLR lenses. I find the bulk of a Canon 50/1.2 L ridiculous compared to manual lenses of the same speed.

The EF 50/1.2 L is almost 9cm in diameter at around 600g. Progress?
 
I think there is a recent Pentax 40mm pancake and an old one from the 70s or 80s. Athe first with AF, the second without.
Which lens do we talk about? So far about both I think :)
 
Griffin said:
And why don't they make more lenses this way? Is it related to the focal length and image circle? Are there any drawbacks on this design? I'm just curious.
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Often the design for a lens like that will be based on a Tessar or alike, the more if it is not faster than f2.8. The 40mm focal length helps too if used on an slr, shorter and a retro focus optical solution has to be used, longer the telephoto solution to keep the lens shorter than the focal length. Not all are Tessar designs though. the recently introduced Canon 40mm is a 6 element design. With Tessar types the resolution degrades more to the corners than with Gauss, Plasmat etc designs. Bokeh is often one of things sacrificed in pancake lenses.

--
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Almost sliding off topic here, has anyone tried that Canon 40mm? opinions?

I think it's somewhat disingenuous to criticise the fact that the Canon 50 1.2 for being "almost 9cm in diameter at around 600g" because the front element is 72mm as opposed to 49 in the Pentax model, so there's a lot more glass in the Canon model, plus the neccesary gubbins to shift that extra glass around, so it's not just due to newer designs being bloated

That said I do greatly enjoy my Pentax lenses on my ME Super and it's very handy that it slips into a jacket pocket
 
BlackXList said:
I think it's somewhat disingenuous to criticise the fact that the Canon 50 1.2 for being "almost 9cm in diameter at around 600g" because the front element is 72mm as opposed to 49 in the Pentax model, so there's a lot more glass in the Canon model,
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The larger filter covers the whole lens, not only the front element which should be about the same in diameter as any other 50mm f1.2 lens.

Here is a picture:
http://www.kenrockwell.com/canon/rebel-xti.htm
 
You're absolutely correct there, my mistake, even so the amount of glass in it is significantly more than the other Canon 50s (differing max apertures I know) plus the autofocus mechanism of course, so I think it's a little odd to expect parity with older manual focus designs.
 
As far as I can tell there are three such lenses: M, limited, and the Mark Newson K-01 lens. Which are you talking about or does it matter. I think it might, because the OP asked about image circle; two are APC-s and the other may be FF.
 
charjohncarter said:
As far as I can tell there are three such lenses: M, limited, and the Mark Newson K-01 lens. Which are you talking about or does it matter. I think it might, because the OP asked about image circle; two are APC-s and the other may be FF.
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yes, it covers the image circle of fullframe, tested :)

charjohncarter said:
You might want to look at these, it seems it is a good performer. Not like someone above says:

http://www.pentaxforums.com/lensreviews/SMC-Pentax-DA-40mm-F2.8-Limited-Pancake-Lens.html

and this is the K-01 lens which is good just not quit as good. But at $249 it is a deal:

http://www.pentaxforums.com/lensreviews/smc-pentax-da-40mm-f2.8-xs.html

Sorry no image circle information on these sites.
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both da 40 limited and da 40 xs (mark newson k-01 lens) cover image circle of fullframe
http://www.pentaxforums.com/forums/pentax-slr-lens-discussion/31629-da-lens-full-frame-test-shots-thread.html
http://www.clubsnap.com/forums/pentax-ricoh/1058470-da40xs-tested-film-mz-s-da40xs-kodak-gold-200-a.html
http://www.clubsnap.com/forums/pentax-ricoh/1151257-images-pentax-smc-pentax-da-1-2-8-40mm-xs.html
 
A "really" tiny lens is the Industar 50-2 50/3.5 M42 lens. Here's a shot of one with my old Pentax ME with M 50/1.7 lens mounted and the DA 40 2.8 Limited keeping them company. The 40 would be smaller if it didn't have the rear cap on but it's still not a whole lot smaller than the M 50...
 

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Thank you OceanPriest, at least someone answered one of the OP's questions (finally). I use an ZX-5 similar to your camera. I don't understand why more cameras were not made this way: shutter speed DIAL and APERTURE ring. You really know where you are, and if you want; complete auto. The auto is for the digital types that want to shoot film once in a while.

To help the OP maybe a little (as I only have one close to 40mm lens); my 40mm lens (maybe it is a 42mm) on my (RF) Olympus 35RC is really the best lenses for 35mm I have.
 
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