[easyreeder]

The kids and I had a minute to test four K mount lenses.

43mm Pentax Limited
vs
50mm Pentax M (1.4)
vs
50mm Pentax M (1.7)
vs
50mm Sears MC (1.7)

Constant: F 2.8 ISO 100 1/30

Below, or .

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Last edited by easyreeder; 11-09-2014 at 06:44 PM. Reason: oops

[LensBeginner]

Interesting comparison and a nice set you have there!
Where did you focus, the eyes?

[johan kruger]

lol funny kids you have there.... mine normally would not sit this still.

but good test.

[easyreeder]

Interesting comparison and a nice set you have there!
Where did you focus, the eyes?

Yes, we were just messing around but it was interesting. Yes, eyes. These are lower res, but the 43 was the sharpest, with the Pentax 50 1.7 next and the Sears 1.7 next. I realized after we were finished that I have a Pentax 50 A 2.0, which I should have included. It didn't occur to me to get it out because I've already earmarked it for my wife, ha, because I think it's much softer than the others.

[LensBeginner]

Yes, we were just messing around but it was interesting. Yes, eyes. These are lower res, but the 43 was the sharpest, with the Pentax 50 1.7 next and the Sears 1.7 next. I realized after we were finished that I have a Pentax 50 A 2.0, which I should have included. It didn't occur to me to get it out because I've already earmarked it for my wife, ha, because I think it's much softer than the others.

You've no idea how many test charts I've shot, then dismantled the whole setup, and then realized I could have done something different/more (lenses, apertures, etc.)!
Another good reason for messing around another afternoon at some point in the future!

[savoche]

Thanks for sharing!

The 43 looks to have a bit brighter exposure than the Ms, and also maybe than the Sears. Interesting. And also surprising (at least to me) that the 1.4 looks softer than the 1.7 at 2.8.

[MarkJerling]

Which again reinforces for me why I like my cheap Pentax-M 50mm F1/1.7!
Thanks for posting.

[easyreeder]

Thanks for sharing!

The 43 looks to have a bit brighter exposure than the Ms, and also maybe than the Sears. Interesting. And also surprising (at least to me) that the 1.4 looks softer than the 1.7 at 2.8.

The 43 and the Sears were the brightest. The M 1.4 was for sure the darkest. At full resolution, to my eye, the bokeh on the 1.7 was the most pleasing, the 1.4 next. The Sears especially had some color separation in the out of focus area on the upper right.

[Naruto]

Between different brands, I own over 25 lenses of 50mm, including SMC Tak, M50 1.4, two M50 1.7, an M50 2, DA 50 1.8. I also own the 3 FA limited. My test results depend on 1) presence of objects leading to PF 2) distance. Unfortunately, there is today so much variation in the old lenses samples that I am afraid the conclusion can not be generalised.

However, it is nice to see your test and I believe that your result for the 43mm remains true.

[easyreeder]

Between different brands, I own over 25 lenses of 50mm, including SMC Tak, M50 1.4, two M50 1.7, an M50 2, DA 50 1.8. I also own the 3 FA limited. My test results depend on 1) presence of objects leading to PF 2) distance. Unfortunately, there is today so much variation in the old lenses samples that I am afraid the conclusion can not be generalised.

However, it is nice to see your test and I believe that your result for the 43mm remains true.

I don't think I've had 25, but I've had a bunch I've gotten rid of. The Rokinons and Chinons, for example, which were fun but I was pretty confident didn't stand up to the Pentaxes.

What do you think of that Tak? Is that the 1.4? I'm curious about it.

Hmm, I do also notice that the 43 has more distortion. I didn't really expect it to be quite as pronounced as it is. With the crop I suppose the focal distance is fairly diff.

[MarkJerling]

I must say, not one of these jump out as 'poor'! They are all pretty good. It's hard to pick a favourite!

[easyreeder]

I must say, not one of these jump out as 'poor'! They are all pretty good. It's hard to pick a favourite!

That's really true! My ten year old daughter liked the sears, and I can see why. The Pentax 1.4 isn't really in its strong suit here, either, and it holds up.

[MarkJerling]

That's really true! My ten year old daughter liked the sears, and I can see why. The Pentax 1.4 isn't really in its strong suit here, either, and it holds up.

It would be interesting to see a comparison with a closer group of diverse objects.

[Naruto]

I don't think I've had 25, but I've had a bunch I've gotten rid of. The Rokinons and Chinons, for example, which were fun but I was pretty confident didn't stand up to the Pentaxes.

What do you think of that Tak? Is that the 1.4? I'm curious about it.

It is the 1.4. I like it, specially the way it feels when I manually focus with it. I think it is similar to the Canon FD 50 1.4 I use on NEX.

My M 50 f1.4 is sharper and has better bokeh than my M50 f1.7. It is the one I prefer for close up pics.

[LensBeginner]

The 43 and the Sears were the brightest. The M 1.4 was for sure the darkest. At full resolution, to my eye, the bokeh on the 1.7 was the most pleasing, the 1.4 next. The Sears especially had some color separation in the out of focus area on the upper right.

I've never thought about comparing exposures... it is a great idea (provided that you can maintain a constant illumination), as I've always wondered about the t-stop of old lenses... I mean... less glass (4, 5 elements) should mean more light all other things (coatings, glass quality, thickness) being equal...
Another excuse to set up a test!

Last time I did 50mm f/1.7, 55mm f/1.8 and 40mm f/2.8 XS... pretty interesting comparison actually...
Turns out that the fifties are at their sharpest around f/5.6 and you can really see the softness caused by diffraction at f/8 on a 16MP body... which is just as it should be...