I think I got a defective Caltar II-N 300mm lens

[John NYC]

Well, after a couple outings shooting 8x10 with the used Caltar II-N 300mm I bought from keh.com and the g-claron 240mm I bought from a forum member here, I have concluded that there is something fatally wrong with my Caltar 300mm. I cannot take a sharp shot with it to save my life. Meanwhile, every single picture I've taken with the g-claron is razor sharp. The difference is not slight. The 300mm pictures are actually blurry, and in a weird way.

So, I've written keh to see if they will exchange it. Unfortunately, I bought it back in December as the first piece of my 8x10 kit and I wasn't able to try it out earlier. (Actually I did take an indoor polaroid using it on my 4x5, but I don't think that was high enough resolution to see the problem.)

My question is now... what is this lens worth to sell? Will someone buy it for just the Copal 3 shutter? (The shutter is accurate according to the pictures I took.)

[lenser]

John,

This is a wildly off the wall possibility, but I did this with a 210mm Caltar II on my Zone VI when I failed to carve out sufficient depth on my lens board.

If yours is self mounted, and on a thick wooden board, you may not have it thin enough to fully seat the rear element on the shutter mount. If that's the case, you will be off focus.

Once I realized what I had done and that the case for the rear elements were impeded by the board and then routed the necessary area deeper, I was home free.

Tim

[John NYC]

John,

This is a wildly off the wall possibility, but I did this with a 210mm Caltar II on my Zone VI when I failed to carve out sufficient depth on my lens board.

If yours is self mounted, and on a thick wooden board, you may not have it thin enough to fully seat the rear element on the shutter mount. If that's the case, you will be off focus.

Once I realized what I had done and that the case for the rear elements were impeded by the board and then routed the necessary area deeper, I was home free.

Tim

Lens board was made by Bruce Wehman. It's a Wehman field camera. I doubt he got it wrong. But you did make me think of something. On both recent shoots, it was kind of windy. I seriously doubt if it was only windy when I was using the 300, but I am going to make sure this weekend by making one more test shot with it; no camera movements, just infinity focus from my roof.

EDIT: But you know what? I just got a linhof board adapter from Bruce. So, I'm going to test your theory just to be certain by taking the shot this weekend with the lens mounted on the camera that way.

[Ed Richards]

Even the same wind will be a lot more trouble on a 300 than a 210. If you still have that polaroid, take a magnifier to it - it is the ultimate high rez contact print and should be fine for showing sharpness.

[ic-racer]

From my own observations with a loupe on the light table and that big lens resolution database, my impression that many of those big 300mm plasmats are not the sharpest lenses. I usually only enlarge to 2x so my prints are fine but I can tell on a 55" enlargement. I still love my 300 though! It is bright to focus, and has a huge image circle and those are its strong points.

All things need perspective so what I am talking about is looking through a 8x loupe or a 55" enlargement.

My 300mm does not produce what would be called "blurry pictures" as you have obtained so you certainly may have a lemon. Perhaps it has a rear cell from different lens or something.

When testing it try opening up a few stops to f22 it may be sharpest around there.

[Jim Galli]

I'm sure KEH will treat you nicely. I think I have some 300mm cells from a shutter I robbed for a 355 G-Claron a couple of years ago. I can look if you want. It's really unusual for one of those to just be 'bad'. Cobble a Nikon digital to the back of the camera and focus through the nikon prism on something that should render sharp and take some digital snaps that you can blow up on your crt. Maybe you can figure out what you're really getting or if something is actually going haywire in that lens.

[Steve Hamley]

You might try this: open the shutter and iris, and try to project the image of a bare light bulb on the wall. If you can see the filament sharply, the lens is sharp. If there's a "fatal" problem, this test might show it. Compare to your G-Claron and see if there"s an observable difference.

Cheers, Steve

[John NYC]

One thing is certain. The g-claron has never produced an unsharp image (not one) so far. This lens has produced unsharp images every time (about four frames so far).

I studied the images and I can see why I missed the problem in my close range Polaroid test on 4x5. The images are not AS blurry on items in the foreground, but as you go back toward infinity a sort of double image starts occurring. At midrange objects, it has the effect of blurriness because the double images are so close. Between the midrange objects and the really far away objects, you start seeing it is really a double image (especially on things like lettering on signs). At infinity, objects have gotten so small that they just look blurry. So I looked at those objects with the double images. In every frame they are double images left and right. You'd think if it were wind, there would be some randomness among the four pictures I took and sometimes the double images would not be so strictly left-right beside each other.

[Steve Hamley]

Double image? Start looking for a small hole somewhere like an unplugged flange mounting screw hole. Sounds like a hole is maybe acting as a pinhole "lens".

Cheers, Steve

[John NYC]

Double image? Start looking for a small hole somewhere like an unplugged flange mounting screw hole. Sounds like a hole is maybe acting as a pinhole "lens".

Cheers, Steve

No holes that I can see anywhere. Plus my exposures were right on the money.