[pres589]

A couple days ago I stopped in the local camera shop and found this very interesting (to me anyway) lens;



I think it's an offshoot of the Vivitar primes from the 70's and 80's but I can't find anywhere on the Internet that talks of a Kalt in Pentax K. This is not an M-type screw mount. So I mount it on my K-5 II and start playing around. This is a full manual lens with an aperature ring and I felt this would be a great lens to really learn on.

And then I get pictures like this out of it;



Fullsize with in-camera jpeg compression here; http://i1172.photobucket.com/albums/r571/djronnebaum/Kalt%2028mm/kalt_house_...psfacb2ccd.jpg

This was shot with an f-stop of 11 and the camera set to auto. I played around a little and they're all some version of this; blurry and out of focus. I shot this off of my covered porch so I was in the shade. To see if my camera is suddenly not in good shape, I took the following with a Pentax 18-55 kit lens from 2006;



Fullsize here; http://i1172.photobucket.com/albums/r571/djronnebaum/Kalt%2028mm/kit_house_full_zps09395740.jpg

I want to think there's something I'm not doing correctly with this thing but maybe this just isn't a good lens, or isn't a good lens for an APS-C DSLR? I can get fairly decent focus up close but it's a bit of a roll of the dice as far as getting there... focusing this thing is a real challenge. And using the live preview usually gets me results that are not as good as using the viewfinder.

Any suggestions? I've been lurking around this forum for a bit and really appreciate it as a resource so I hope I'm asking this right. Oh, and the colors are a little off because of how saturated images are when using the Kalt, so I tweaked the saturation and hue a little for that lens, and just ran with those settings with the 18-55 mounted. The "Bright" color etc setting from the factory was really blown out, especially reds.

[marcusBMG]

Do you get sharp pics close up?

This is not an M-type screw mount

Your terminology is off here. Normally a screw mount lens is the ubiquitous M42 thread, used by a number of camera/lens manufacturers inc Asahi Pentax. Is that the mount? And if it is what adapter are you using on the camera? You will lose focus with a rimmed adapter exactly like the pic. see here

[Kozlok]

Does it work better focused close up? Could be that the focusing helicoid is out of alignment. Looks like it'd have to be out by a mile, though!

Maybe the lens is just junk. I have an old Formula 5 28mm that I got for $10 or so, and it's miles better than this!

[pres589]

Do you get sharp pics close up?



Your terminology is off here. Normally a screw mount lens is the ubiquitous M42 thread, used by a number of camera/lens manufacturers inc Asahi Pentax. Is that the mount? And if it is what adapter are you using on the camera? You will lose focus with a rimmed adapter exactly like the pic. see here

There is no adapter. The lens I have is a K-type mount. I was trying to make sure that people would understand that, while I can find no reference to a Kalt 28mm with a K mount, that's what I have in hand. I found multiple references to a Kalt with the M42 screw mount.

Kozlok, it does do things better close up, here's a couple pictures I just took;

My watch, with an F-stop of 5.6;

http://i1172.photobucket.com/albums/r571/djronnebaum/Kalt%2028mm/IMGP0647_zpsb5da3f83.jpg

My kit lens, with an F-stop of 2.8;

http://i1172.photobucket.com/albums/r571/djronnebaum/Kalt%2028mm/IMGP0650_zpsfd7c9076.jpg

[Na Horuk]

Make sure that it actually stops down to the selected aperture when you take the exposure.
also, you can dismount the lens and shine a flashlight down to see how clear it is, if it has any visible problems.

[elliott]

You can't use Av mode with a K mount lens that doesn't have A contacts, the lens doesn't stop down. You must use M mode and the green button.

[thazooo]

Looks like the results I got with a Soligor 28mm f2.8. I use mine as a Paper Weight now.
Bad lens is a bad lens.

[pres589]

You can't use Av mode with a K mount lens that doesn't have A contacts, the lens doesn't stop down. You must use M mode and the green button.

I'm aware. I'm using the aperture ring which does affect the blades. There's a difference in pictures taken at various f stops. I shot the house picture in auto just to let the body deal with iso and exposure. I can play more with it but responses here aren't encouraging.

[aleonx3]

I'm aware. I'm using the aperture ring which does affect the blades. There's a difference in pictures taken at various f stops. I shot the house picture in auto just to let the body deal with iso and exposure. I can play more with it but responses here aren't encouraging.

Sounds like it has been modified as K-mount but without the lever (so it functions similar to modified m42 without A/M switch). It appears to me that you can try to do AF adjustment on the camera. Try to do the adjustment test with something closer so you can tell whether it is FF or BF, hopefully you will find the adjustment work within the +/-10 range. Good luck...

[elliott]

I'm aware. I'm using the aperture ring which does affect the blades. There's a difference in pictures taken at various f stops. I shot the house picture in auto just to let the body deal with iso and exposure. I can play more with it but responses here aren't encouraging.

The one with the kit lens at f11 is 1/100s, the one with the 28 is 1/2500, that 28 was wide open and not at f11 regardless of what the ring was set on. When not mounted you can turn the aperture ring and it will move the blades, but once you mount it the lens is held wide open with the aperture lever. In Av mode the camera is not going to release the aperture lever to allow the lens to stop down.

I can see this clearly in the EXIF, you were using Av mode, you can't use Av mode with that lens.

For f2.8 that doesn't look terrible, by f5.6 it should look pretty good.

EDIT: Looking again, even in M mode it is not going to work properly right now. That mount is non-conductive and not shorting the contacts of the camera mount. The camera think it is an M42 lens, it is not going to try to release the aperture lever. You need to short the contacts for it to work, either by adding some foil or removing the anodizing from the mount. It says "M42 or no lens" in the EXIF, it should say "K, M lens".

[pres589]

elliot: Whoa, ok, thank-you! I'll look for instructions on where to remove the anodizing to properly mod the lens mount.

[splash_fr]

take a small strip of aluminum foil to shorten the contacts of the mount on the camera before putting the lens on. i'm doing the same with an old porst lens that is non conductive as well.

[marcusBMG]

Its just the data contact that needs to be shorted - thats the one at the half past six position ie the bottom end one as you're looking at the camera mount,

T-mounts have similar issues but work in Av mode without restriction because there is no aperture lever. There are a few lenses out there with black K-mounts, they typically date from the mid seventies, just when the K-mount was introduced.
Another simple possibility: try the lens not fully mounted ie turn it back from its position fully on with the locking pin clicked in (but not so much that it falls off!). This disengages the aperture lever.

Note that both using foil, and partially mounting the lens, can introduce mirror flopping issues!

The poor iq could be:
- simply the lens is rubbish wide open
- there is an optical fault like a loose element, incorrect repair reassembly, collimation out....
- there are focus issues
Some more diligent testing can help to establish what. eg set up on a tripod, use a page of news print on a wall, do test pics through the range of f stops. Set on f2.8, infinity focus, and walk to the the page using live view, noting if at a certain distance the page comes into focus.

[pres589]

marcusBMG: The back side of the mount, where the lens touches those contacts, is indeed black and seems like paint or a similar coating. I have the lens marked as to where I need to hit it with a little sand paper (I don't like the idea of using foil there, which I know would work electrically, but could fall into the body or something else happen; I'd rather sand on a cheap lens then potentially damage a body that cost me $600). The aperture ring is definitely having no effect on pictures; took a low light shot at F2.8 and then again at F16 and they look pretty much the same. I'm not sure why I didn't notice this earlier... Thankfully this isn't part of my day job.

When I get a chance I'll see what I can do with the newsprint test.

[marcusBMG]

I have the lens marked as to where I need to hit it with a little sand paper

Remember you need to make a circuit so in that case I would take off the paint for ALL the contacts. Thats what I did on a T-mount. I made a mask by making a pencil rubbing of paper held onto the camera mount used that to scratch the positions and then used a dremel bit by hand to take off the anodising. But TBH the connection is iffy. For testing use foil: fold a small piece into an oblong shape about 1/4" by 1/2", use a finger/thumb to hold in position as you mount the lens. Also try partially mounting as suggested, quickest and easiest.