Pentax-M 40 2.8 pancake

[truls]

Quick quality test of this lens, Olympus Pen micro 4/3, PK-adapter. I have had a lot of fun with this lens, it is so small both camera (Pentax MV1) and lens fits in a big pocket. Here is the lens:



The AA-size battery besides illustrates how small the lens is.
Lens aperture range f2.8-f.22

Center:


It has good center sharpness all over, it deteriorates at f.16 and 22. The image got darker, is this maybe due to change in contrast?

Corner:


From f5.6 - f.16 ok sharpness, also loss in contrast at f2.8, f.11-f.22.

Sample image @f5.6:


100% crop:


Fomapan film:


Conclusion: It is an ordinary lens, no better or worse than others. It has a somewhat cult status for some reason. The price on aution sites are way beyond the optical quality. I think the lens is good normal quality, the advantage is high portability. E.g. a Pentax MV-1 combined with this lens is a high quality outfit when light luggage is required, it takes not much more space than a compact camera. Of course compared to new small digital compacts it cannot compete.

Edit: The 40mm focal length (on film) is most useful. It is just a bit narrower than 35mm. It is easy to compose images, both to include elements as the lens can mimic a wide, also to use small depth of field to isolate picture detail.

[philbirch]

I had one of these, I got it for free. Tried it and found it a little ho-hum quality wise. I sold it for £45 on ebay within minutes of putting it on.

[Stan]

These days, most anything that one can hang the moniker of "pancake" on seems to have an inflated following. That being said, I have a soft spot for them myself, but refuse to pay for it so therefore, I go without. I do have one of the "E" series Nikon 50mm that's often called a pancake, although compared to your Pentax, is nowhere close. I used to lust after that 40mm, until I got out of Pentaxes. Always dreamed of how compact my ME-Super would be with it on there!

[truls]

Jul 22, 2014 9:56:44 GMT -5 Stan said:

These days, most anything that one can hang the moniker of "pancake" on seems to have an inflated following. That being said, I have a soft spot for them myself, but refuse to pay for it so therefore, I go without. I do have one of the "E" series Nikon 50mm that's often called a pancake, although compared to your Pentax, is nowhere close. I used to lust after that 40mm, until I got out of Pentaxes. Always dreamed of how compact my ME-Super would be with it on there!

Stan, your Nikon 50mm E-series has a much higher image quality than the Pentax pancake, and it it not much bigger either. There are several other pancake lenses, Minolta 45/2.0 - Konica 40/1.8 - Industar 50/3.5 m42, and more. Also the new digital cameras have their own pancake lenses. I know Olympus Pen m43 have an incredible small zoom lens (14-42MM/3,5-5,6). Also Nikon have a pancake, 45/2.8.

[hansz]

Also Prakticar 2,4/50

[philbirch]

I like a cheese and ham pancake.

[hansz]

Phil, try a cheese and paprika pancake.

[belgiumreporter]

Nikon probably made the first pancake lens ever, introduced  in 1968 the 45 2.8 GN nikkor. GN standing for guide number as this tiny lens had a coupled diafragm-focus mechanism. You set the guide number of your flash on the lens and when focussing the lens will set the diafragm to the according aperture needed for the distance set. It came in very handy as a reporters lens in the day that electronic flashes weren't computer controlled and gave of their full power by each shot. The 45GN was made so small not because of the hype of pancake lenses ( i doubt they were called that in 1968) but for the practical reason to lower the weight of the camera that was combined with a heavy (pro) flashgun. Optical performance was good but not exeptional. I also believe it was one of the cheapest nikkors in it's day, without the hype it was just a humble tessar design lens with a limited field of use.

[truls]

Jul 23, 2014 3:51:03 GMT -5 belgiumreporter said:

Nikon probably made the first pancake lens ever, introduced  in 1968 the 45 2.8 GN nikkor. GN standing for guide number as this tiny lens had a coupled diafragm-focus mechanism. You set the guide number of your flash on the lens and when focussing the lens will set the diafragm to the according aperture needed for the distance set. It came in very handy as a reporters lens in the day that electronic flashes weren't computer controlled and gave of their full power by each shot. The 45GN was made so small not because of the hype of pancake lenses ( i doubt they were called that in 1968) but for the practical reason to lower the weight of the camera that was combined with a heavy (pro) flashgun. Optical performance was good but not exeptional. I also believe it was one of the cheapest nikkors in it's day, without the hype it was just a humble tessar design lens with a limited field of use.

What was the first pancake lens? I do not know, but Minolta Auto Rokkor 45/2.8 came in the 1960s sometime. Any comments the first SLR pancake?

[philbirch]

Wikipedia says a 1902 Tessar was an early example, although I suspect it wasn't on a SLR. The article notes that the Nikon GN lens of the 60's and 70's is 'a notable example' pancake lens on wikipedia

[daveh]

I recall that there was an Industar lens of the late 1960s. I have a Cosina lens from the 1970s, but I've no idea what its production run was (or maybe still is).

[philbirch]

Jul 23, 2014 15:38:45 GMT -5 daveh said:

I recall that there was an Industar lens of the late 1960s. I have a Cosina lens from the 1970s, but I've no idea what its production run was (or maybe still is).

Perhaps the Industar 50 supplied on cheaper Zenits

[hansz]

This Industar applies to the name:

IMG_1233 by hanszeiss, on Flickr

A 1968 version in M39 Zenit thread. (Not to be confused with the Leica 39 thread... which has a different flange-to-film distance)

[truls]

Yes, the Industar must be one of the early pancake, it is a good one too.

While on topic, I found at the auction a Rikenon pancake, 45mm 2.8:



It is not much info on the net about this lens, is it a Tessar copy, or a 5-element contruction as the Pentax 40mm? It has been on the auction a long time, no wonder, the price is high. The close focus at 0.6 meter is the same as Pentax 40mm, is it a rebranded Pentax lens?

[Stan]

I don't know for a fact, but over the course of the 70's Ricoh and Pentax product lines became closer and closer with many products having similar specs and feature sets. This became especially true after Ricoh switched to the "K" mount.  I've never seen that particular lens, though it's physical characteristics are remarkably close to the Pentax 40mm.

I have on occasion had some mad moments when I've thought of acquiring the Nikkor 45mm GN lens, then I realize that on a DX sensor'd camera like my D40 and D300, it's focal length isn't of great use. I'd definitely consider the Konica Pancake to go with my TC though.