[clockworkrat]

I've got the opportunity to buy a pentax M 200mm F4 for a reasonable price, but after testing it it looks a bit cloudy. Is this a known characteristic of this lens, or should it have good contrast? I only shot at 5.6 and 8.

[ZombieArmy]

You'd have to give example shots. I know the 200 M isn't stellar with contrast (or CA) but it shouldn't be particularly "cloudy".

[stevebrot]

Is this a known characteristic of this lens

No, "cloudy" is not a known characteristic of the M 200/4. Contrast is fairly typical for the breed and it benefits from a little deeper hood than the one built onto the lens.

Here is one of my better shots with my copy:




...and another (back-lit) shot taken at a longer distance:



I also have a Vivitar 200/3.5 (Komine) of about the same vintage. That lens is both bulkier and heavier than the Pentax, but also is a little sharper with better contrast.



Steve

[ZombieArmy]

Here's a full size shot from a baseball game with only minor post done, don't really see any cloudiness.

http://puu.sh/iLsBv/e194fb0c3c.jpg

And here's a shot of the moon I took a while ago cuz why not!

[stevebrot]

If there is haze on one of the inner elements, chances are it can be cleaned. What does it look like if you shine a flashlight through it?

Good idea...

Dark room, penlight, shine obliquely through front while looking through back. Repeat with light shining through back.


Steve

[lytrytyr]

I've got the opportunity to buy a pentax M 200mm F4 for a reasonable price, but after testing it it looks a bit cloudy. Is this a known characteristic of this lens, or should it have good contrast? I only shot at 5.6 and 8.

There are so many copies of this lens for sale, generally at very reasonable prices,
that it's really not worth bothering with a potentially poor one.

My copy is not at all cloudy. The lens is sharper towards infinity than it is closer in.

[Adam]

Could just be slight overexposure, too.

Adam
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[stevebrot]

Could just be slight overexposure, too.

OP has disappeared...


Steve

[ScooterMaxi Jim]

I agree with the general direction of comments, especially the point made by Lytrytyr regarding sharpness and contrast better near infinity.

Obviously, if you can look at the lens to see if it's clean overall, that helps. Shot RAW at the longer distances, it's a fun lens to have because it's very small for 200 f/4, has the nice built-in retractable hood, and typical superb M build. It is cheap for a reason, though, and the contrast is pretty low even on a clean copy. It takes some work with good RAW conversion to get really strong shots and eliminate the CA, but the final result can be quite impressive as shown above (especially in good light).

Still, I would rate the even-smaller 75-150 from the same era a step higher overall, especially when it comes to contrast and shooting at closer distances.

[clockworkrat]

Obviously, if you can look at the lens to see if it's clean overall, that helps. Shot RAW at the longer distances, it's a fun lens to have because it's very small for 200 f/4, has the nice built-in retractable hood, and typical superb M build. It is cheap for a reason, though, and the contrast is pretty low even on a clean copy. It takes some work with good RAW conversion to get really strong shots and eliminate the CA, but the final result can be quite impressive as shown above (especially in good light).

Thanks, that's the information I was looking for.

Here are my test shots exported from Darktable with no edits.







The second one in particular bothers me because I was shielding the lens from the sun and pointing at what should be a really high contrast scene.

[stevebrot]

Thanks, that's the information I was looking for.

Here are my test shots exported from Darktable with no edits.







The second one in particular bothers me because I was shielding the lens from the sun and pointing at what should be a really high contrast scene.

Unless it was a foggy day, those results are not typical. OTOH, your import settings to Darktable might at fault. Do out-of-camera JPEGs show the same low contrast?


Steve

[ScooterMaxi Jim]

Definitely pass. It must have haze or fungus. It really shouldn't have IQ all that much different than the 50-200 at the long end, probably a bit sharper and just a bit less contrast. Keep an eye out for one in better shape - they're a good deal with so many of them typically available if you wait just a bit.

[clockworkrat]

Unless it was a foggy day, those results are not typical. OTOH, your import settings to Darktable might at fault. Do out-of-camera JPEGs show the same low contrast?

I just use RAW these days, but from other lenses I do get better contrast.

Definitely pass. It must have haze or fungus. It really shouldn't have IQ all that much different than the 50-200 at the long end, probably a bit sharper and just a bit less contrast. Keep an eye out for one in better shape - they're a good deal with so many of them typically available if you wait just a bit.

Cheers, may do.