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11-09-2010, 05:23 PM - 4 Likes   #1
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50ish mm Infinity Shootout (K mount)

I think we can all agree that most primes have a sweet spot in terms of focal distance and aperture. If you've wondered how the 50ish MM lenses stack up, this is as scientific of a test as I'm interested in doing. I think taking pictures of paper charts is a silly waste of time and resource. If I want to know how good a lens is, I'll go out and take real pictures with it.

Index of /Photos/50mmShootout

Lenses:
Pentax A 50mm f1:1.7
Pentax A 50mm f1:1.4
Pentax A 50mm f1:1.2
Pentax K 55mm f1:1.8
Pentax DA*55mm f1:1.4
Voigtlander 58mm f1:1.4

There are no special pictures here, just a progression of shots from Wide open to fully stopped down. All photos were taken in M mode and the meter centered as best as possible (similar to using Green Mode but I didin't). All photos received Exactly the same processing. That is, I processed one in ACR and Copied the entire settings set to the rest. All photos were taken from exactly the same position, SR on, No tripod, and with one exception, ISO 80 on the K5. Exifs are in tact on all photos. First in each sequence is wide open and each progression is closed down one full stop. With the exception of the DA*55, these are all manual focus at or near infinity. The DA*55 was allowed to autofocus and the same target was used each time.

With these tests, I am looking at the steps on the pole to judge. Use your own criteria if you wish, that one works for me. I've chosen a winner but won't tell you which I think it is. I thought about not even telling which lens for which photo but that requires too much record keeping on my part, and I just don't care to go that far.

I'll do the screw mounts in my collection at a shortly later date (Tak 55f1.8, Tak 50f1.4, Mamiya 55f1.4, Sears 55f1.4).




Last edited by pjv; 08-04-2017 at 11:50 PM. Reason: remove swearing
11-10-2010, 12:50 AM   #2
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I do love these shootouts, and I appreciate the time and effort required - so well done JeffJS, and thanks!

I had a quick look at the f4 images for all the lenses (as I expect a decent 50 to be razor-sharp at f4), and my observations (for what they're worth) are as follows:

1. DA* 55/1.4 isn't sharp.

2. The 55/1.8 and 50/1.7 seem to be slightly under-exposed compared to the others. This may affect the assessment of sharpness (positively), colour and contrast.

3. I would rank sharpness as follows (best first): 50/1.7, 55/1.8, 50/1.2, Voigt 58/1.4, 50/1.4. Very surprising result, flying in the face of conventional wisdom, so I'm probably talking rubbish.

4. The Voigt 55/1.4 and 55/1.8 seem slightly low on contrast.

5. The 55/1.8 and 50/1.7 seem slightly warmer in terms of colour.

But the main conclusion is that you can't go far wrong with a vintage 50! Will look forward to your M42 test...
11-10-2010, 01:06 AM   #3
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Thank you for your observations. This took me about an hour to shoot so lighting did change slightly from lens to lens. My best effort was made to keep the meter centered on the wire tower for exposure but it's entirely possible that I missed it by a third or so in some shots as well. I don't know about the DA*55. I know it to be a sharp lens in most situations. Perhaps I should have manual focused it and left it at infinity as I did with the rest of the lenses. At that distance, that tower is a pretty small target so it may have back focused on the building 20 or so yards behind it. Then again, maybe not. There may also be a little camera shake going on in some of these too, though at the shutter speed of 1/1600 for f4, I'd be surprised if that were the case.

This one is taken at f4.5 though not at infinity..

I wasn't even looking at contrast and color, only sharpness but you're free to take from these what you wish and can. It's certainly there to see. I made sure they all had the exact same DNG>JPG conversions in APR so exposure differences are entirely my doing in the initial exposures.

11-10-2010, 01:43 AM   #4
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QuoteOriginally posted by JeffJS Quote
This one is taken at f4.5 though not at infinity..
That one certainly looks nice and sharp and contrasty - even in the corners, so, you're absolutely right, we mustn't draw too many conclusions from a single example.

Regarding exposure - it's extremely difficult to get exactly the same result across all lenses, I think, so I certainly wasn't being critical of you here! It's just that I reckon it's an often underestimated factor when it comes to comparisons, and it may be the reason that I judged the 50/1.7 and 55/1.8 to be sharper than the others.

As I say, though, I don't think you can go far wrong with any of these lenses, and it'll often come down to personal preference in the end.

11-10-2010, 02:15 AM   #5
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QuoteOriginally posted by m42man Quote
That one certainly looks nice and sharp and contrasty - even in the corners, so, you're absolutely right, we mustn't draw too many conclusions from a single example.

Regarding exposure - it's extremely difficult to get exactly the same result across all lenses, I think, so I certainly wasn't being critical of you here! It's just that I reckon it's an often underestimated factor when it comes to comparisons, and it may be the reason that I judged the 50/1.7 and 55/1.8 to be sharper than the others.

As I say, though, I don't think you can go far wrong with any of these lenses, and it'll often come down to personal preference in the end.
In hindsight (and I'll do this on the next test set) I probably should have set a certain EV and stuck with that at least throughout each lens. Then I could say that that was held constant. I don't mind people drawing their own conclusions, and certainly invite them to do so (as long as it doesn't get personal ). I've looked at these photos on 2 different monitors, one LCD and a CRT. The photos appear slightly different, in terms of sharpness on each.

On my Laptop LCD, Wide open, I deemed the Voightlander to be the clear winner. Closely followed by the Pentax A1.7, 1.4, 1.2, in that order. The K55 is somewhere in between, and the DA* appeared, in this test, soft, wide open. I didn't look too close on the CRT but I might draw a different conclusion with that screen.

Part of the motivation for this was a recent statement I read saying that the Older lenses couldn't hang with the K5. I'm not finding that to be the case. The oldest lens in This particular set is the K55 and it certainly can perform on the K5. The K55 on the K5.. Kind of a nice ring to it. Too bad it's a borrowed lens.

11-10-2010, 02:39 AM   #6
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QuoteOriginally posted by JeffJS Quote
Part of the motivation for this was a recent statement I read saying that the Older lenses couldn't hang with the K5...
That's interesting - is this because of resolution or dynamic range, I wonder. I have heard it said that the increased DR may make the K-5 images more prone to CA, and maybe this would be a reason for older lenses to be avoided???
11-10-2010, 02:48 AM   #7
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Compare the grass the other side of the water in the wide open shots for the 1.4 and 1.7 lenses. Seems to me the 1.4 has more detail. Which suggests maybe the focusing isn't quite consistent...?
11-10-2010, 03:13 AM   #8
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QuoteOriginally posted by timo Quote
Compare the grass the other side of the water in the wide open shots for the 1.4 and 1.7 lenses. Seems to me the 1.4 has more detail. Which suggests maybe the focusing isn't quite consistent...?
Yes, I see that, and that's quite surprising, as the 50/1.4 is meant to be very soft wide open. It may be because the grass is in the foreground, and as yousay the infinity focus fo the 2 lenses could be different, so the grass may not be in the DOF for the 50/1.7. Or something to do with the fact that the 50/1.7 image is rather darker.

I think it's the other way round at f4 though. All rather puzzling, given the respective reputations of the 2 lenses.

11-10-2010, 04:07 AM   #9
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QuoteOriginally posted by m42man Quote
Yes, I see that, and that's quite surprising, as the 50/1.4 is meant to be very soft wide open. It may be because the grass is in the foreground, and as yousay the infinity focus fo the 2 lenses could be different, so the grass may not be in the DOF for the 50/1.7. Or something to do with the fact that the 50/1.7 image is rather darker.

I think it's the other way round at f4 though. All rather puzzling, given the respective reputations of the 2 lenses.
As I have recently discovered with two 28mm lenses and one FA50/1.7, neither the infinity mark on the lens, nor the farthest travel of the focusing ring, is a reliable indication of whether the lens is actually focused to infinity! They could very easily have been focused differently.

Actually I think the relative softness of the 1.4 (vs the 1.7) wide open is often overplayed. I have both M versions and provided you get the focusing right (difficult) there is a bit of difference in contrast but not much in actual detail.
11-10-2010, 04:20 AM   #10
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In the f/4 comparison images,if you look at the roof tiles on the barn, they are clearly distinct on the A50mm f/1.2 but with the 50mm f/1.7 , they are not quite so clearly defined. you see the same thing with the K 55mm f/1.8 - the voigtlander 58mm f/1.4 comes second to the 50mm f/1.2 in my opinion. I love the rendering of the f/1.2 wide open with that scene, There is far more to a lens than just raw sharpness.

In my experience, Both the A and K series 50mm f/1.2 lenses typically have better micro contrast, which means the lens is able to clarify the distinction between similar tones.
11-10-2010, 08:25 AM   #11
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QuoteOriginally posted by timo Quote
As I have recently discovered with two 28mm lenses and one FA50/1.7, neither the infinity mark on the lens, nor the farthest travel of the focusing ring, is a reliable indication of whether the lens is actually focused to infinity! They could very easily have been focused differently.
This drives me nuts, especially with my 28mm! Whats the best work-around? Is there something I can tighten, to calibrate the focusing ring?

Thanks a lot for all of the work. I think my personal favorite is the the 55* 1.4. I love how the "soft focus" look at 1.4 cleans up so dramatically at just one aperture setting smaller.

Last edited by paperbag846; 11-10-2010 at 04:57 PM.
11-10-2010, 10:11 AM   #12
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QuoteOriginally posted by timo Quote
Compare the grass the other side of the water in the wide open shots for the 1.4 and 1.7 lenses. Seems to me the 1.4 has more detail. Which suggests maybe the focusing isn't quite consistent...?
If you mean MY focusing, it Is consistent. The lenses were set at infinity and left there, in fact, I think they are Still there .. If you mean actual infinity OF my lenses then, that's a different matter. There is a photo in the base directory before you go into any of the 50mm's. That photo was taken with a Vivitar 28mm f2.5 just to show the entire scene. Couldn't tell you the exact aperture, probably f8 or so.

Glad to see people are getting something out of this. Motivates me to continue this project with other lens groups.

PS. Since I went 58mm on the long end, I'll probably add the FA43mm f1.9 Ltd in this group of tests. Stay tuned for a good clear day and some time to put it together.

11-10-2010, 10:41 AM   #13
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Thanks Jeff for doing this. It is a lot of work and an invaluable resource. Sean Carpenter, a former (?) Pentax photographer did something similar. You can find his work and results here

NaCl(I'm just happy that my much loved A 50mm f/1.7 did so well)H2O
11-10-2010, 04:54 PM   #14
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Great work there Jeff! Really interesting to see a set of 50s matched off against each other. My money's on the 43 if you manage to get another clear day for this particular test
11-11-2010, 05:18 PM   #15
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Thanks everybody. I'm glad people are getting something out of this. I've completed it (almost) to the extent I intend to. Still have to finish the Super Takumar 50mm f1.4 (I shook the camera apparently on a lot of the exposures, it Can't be that bad). Here's what I have for you.

I've added the FA43mm f1.9 Limited to the original sets
I also discovered I had an M50 f2.0 and went ahead and tested it as well.
The fore-mentioned M42 lenses were also tested and can be found here

50mm Shootout- Screw Mounts

The entire set is here (once again)

50mm Shootout

The Test Bench....



One thing that became Crystal clear during this process is how Pointless it is to try and judge sharpness on the rear screen, even on the K7/5. If I had gone by that, I would have given up in the first few shots, sold all my stuff, and went back to pencil and paper drawings (or exclusive medium format film anyway)..

Enjoy.

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