[someasiancameraguy]

Hi everyone,

As per my title, I was wondering if anyone hhere has tested both M and DA versions of the 40mm 2.8 to see their differences, especially in regard to vignetting performance on FF sensors?

[Paul the Sunman]

I haven't compared with the 40mm M, but my experience with the SMC DA 40 on the K1 is pretty positive. Only the corners can be an issue. I wouldn't be surprised if the M lens behaved similarly, but people didn't "pixel peep" so much in those days.

[Gary H Perth]

The M 40mm was built for full frame cameras - it matched beautifully with the ME Super (which was a combo that I used for years). I never noticed any vignetting on film, and I would be surprised if it showed significant vignette on a K-1. What a shame I do not have a K-1 to test it with. Of course I am willing to run some tests if somebody gives me a K-1.

If I have time in the next few days, I will put my M40 and DA40 on a Sony A7ii and see what happens.

[robgski]

I own all three versions, the M 40 did not impress me on the K1, though that could be my copy. On the other hand, the DA 40mm Limited and the DA 40XS are both great on the K-1. I've never noticed a vignetting problem.

[aslyfox]

as stated, the M 40, the original " Pancake " is a SLR full sensor lens

you also can look at this thread

which has photos of the M 40, the DA 40 XS, the DA 40 Limited and the FA 43 Limiteds

. . The Pentax 40mm and 43 mm lens club is hereby announced

please post photos taken only with the following lenses to this thread

M 40mm F2.8
DA 40mm F2.8 XS
DA 40mm F2.8 Limited including both the SMC and HD versions

and FA 43mm F1.9 Limited . . .

Read more at: the Pentax 40mm and 43mm Lens Club - Page 16 - PentaxForums.com

there is also this:

Full Frame Coverage of DA Lenses: Comprehensive Test
Which DA lenses cover the full 24x36 mm frame?
By PF Staff in Gear Guides on Jan 7, 2019

Read more at: https://www.pentaxforums.com/articles/gear-guides/full-frame-coverage-of-da-...#ixzz6dmazX3eb

[ZombieArmy]

From what I've seen of the 40mm M is that the rendering is pretty similar to the XS or limited. Given that the xs and limited both do good on full frame and they're suuuper cheap, barely costing more than the M, I'd probably go with them.

[someasiancameraguy]

What I really need to know is the actual vignetting performance as the lens review models show that the last element on the DA versions are substantially smaller than the M version. If the vignetting is significantly worse on the DAs then I'll find an M version to buy so I can also use them for film.

[pres589]

There are not too many Pentax film bodies that I would want to use with lenses that lack aperture rings. I'd suggest knowing what body you want to use before deciding on the M vs. DA 40's. If you want AF and an aperture ring you're probably best off moving over (not up, over) to the FA 43. I also don't know if I'd rather full-time manually focus the DA 40's; the 40 XS actually isn't bad to manually focus. I can't speak to the 40 Ltd.

This is my 2 cents and based on my thinking that it's more important to want to use the lens vs. being concerned about a degree if vignetting. We've seen lots of shared images with the DA 40's on the K-1 and other cameras to know that the image circle doesn't not give a hard edge to darkened corners. I do think there is some light fall-off at wide apertures with all of these lenses on full frame.

[aaacb]

I liked using the da 40 with the super program and K1. With af film bodies the quick shift doesn't work, and i also didn't like the look and feel of a plastic bodied camera with the metal lens. Vignetting never bothered me, though i tended to shoot at f4 and smaller; it's less noticable to me than with the da70 Now I use the fa 43 because of the larger aperture and different rendering, it wasn't the optical performance of the da 40 on ff that motivated this change.

[stevebrot]

I'll find an M version to buy so I can also use them for film.

Then you should get the M-series lens (no aperture ring on DA). FWIW, the DA versions, while similar, do not share optical design with the M-series.

M-series


DA-series variants


Above diagrams lifted from The K-mount Page Web site: http://kmp.pentaxians.eu/lenses/normal/


Steve

[stevebrot]

What I really need to know is the actual vignetting performance

Rear element diameter is no indication of image circle. Unofficial evaluation by Pentax Forums staff indicates two stars (out of three) for FF compatibility, meaning...

Full coverage at some F-stop and focal length combinations

f/2.8 : D
f/5.6 : C
f/11 : A

https://www.pentaxforums.com/lensreviews/hd-pentax-da-40mm-f2.8-limited.html

In the U.S. school system, A is first class, C second class/passing, and D barely passing. I can't see buying the DA if one wants a pancake for FF film or digital work.


Steve

[pid]

the corners of the old M are better than the DA or XS, because they are made for FF. The Corners of the DA or XS are always blurred because the lenses are made for APS-C. But bith lenses have better coating and more contrast than the old M.

[GUB]

There is this thread Is the 40mm 2.8 Pancake really that bad? - PentaxForums.com

[Adam]

I've used both the M and DA 40mm lenses on APS-C and the overall image quality from the DA seemed much better due to improved sharpness and reduced aberrations. I have a hunch the same might apply on FF, except maybe the corners wide-open. Will check to see if we have any FF samples here on the forum.

[stevebrot]

I've used both the M and DA 40mm lenses on APS-C and the overall image quality from the DA seemed much better due to improved sharpness and reduced aberrations. I have a hunch the same might apply on FF, except maybe the corners wide-open. Will check to see if we have any FF samples here on the forum.

Looking on the sample gallery for the DA 40/2.8 Limited and working back from the end, there are K-1 examples.

Pentax DA 40mm f/2.8 Limited samples - Page 5 - PentaxForums.com

FF with the M 40/2.8 are harder to find, though the APS-C examples are impressive.


Steve