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11-28-2010, 07:27 PM   #1
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Soft 400mm f5.6 Tele-Takumar

I have a screw mount 400mm f5.6 Tele-Takumar with manual aperture that takes very soft photos. The problem is that the lens looks fine - no scratches, no fungus, no cloudiness, no apparent separation of elements, aperture is oil free and works smooth. Nothing seems out of place. However, even stopped down the lens is pretty soft. Something definitely isn't right.

Any suggestions/ideas as to how/where to get the lens fixed and what it might cost getting it fixed?

Thanks ahead of time,

Pete

11-28-2010, 10:15 PM   #2
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I'm just thinking out loud here. Are you using an adapter to K mount? If so, is the infinity focus blocked off? The adapter must be absolutely flush with the mount and many 3rd party adapters don't allow infinity focus. Are you focusing past infinity? The 400's allow that to compensate for the increase in barrel length with high temperatures.

If you have done all these, check with the forum's good friend Eric. I just had my M 400/5.6 tuned up for C$100, including re-corking the tripod mount and a full Clean, Lube and Adjust. The company I used was Vintage Visuals in Calgary, Alberta, Canada, so they won't be much help to you in Indiana.
11-28-2010, 11:05 PM   #3
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Thanks, for the suggestions. Yes, I used a screw mount adapter, but unfortunately subjects less than 200 ft are also extremely soft. So it's not an infinity focus issue.

I'll try and look Eric up. In the meantime I'll take a look at your photos.

Thanks again!
11-29-2010, 02:48 PM   #4
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I have the 400mm Tele-Tak, and I don't know if I'd consider it soft per se, or simply an old and undercorrected lens with some prominent aberrations. Probably more the latter. But either way, I agree it's hard to get a really sharp, contrasty shot out of it!

I can't take any test shots right now because my camera is in the shop, but if I have a chance in the next day or so, I'll look through my old shots to see if there's anything I can post that might help you decide whether you have a problem with yours.

I'll see if I can come up with some 100% crops to show detail.

11-29-2010, 02:51 PM   #5
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Is it a large and heavy lens? You might need faster shutter speeds than you are accustomed to.
11-29-2010, 02:53 PM   #6
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QuoteOriginally posted by plieber Quote
Thanks, for the suggestions. Yes, I used a screw mount adapter, but unfortunately subjects less than 200 ft are also extremely soft. So it's not an infinity focus issue.

I'll try and look Eric up. In the meantime I'll take a look at your photos.

Thanks again!
There is a series on my Flickr site where I was testing exposure with my M 400/5.6, which is a very similar lens. There are one or two in my gallery here as well.
11-29-2010, 02:55 PM   #7
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test shots would be of use.
I would suggest a couple of things

First, look at shots on a tripod, and with higher shutter speeds, and

second, take some shots with a flash.

You may simply have focusing errors, because this lens will be hard to focus manually, a split image finder may darken, and the stock viewfinder may display more depth than actuially present.

Try both wide open and stopped down to F8/11
11-30-2010, 02:03 PM   #8
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As promised, here's a shot from my own excellent-condition Tele Takumar 400mm f/5.6. This is pretty representative of the image quality I'm able to get with the lens -- certainly not crisp at the pixel level, and pretty low in contrast, but very usable at lower print sizes.

And as I said, you'll see some chromatic aberration here, particularly in the corners. Most of the waviness in the central portion comes, I think, from atmospheric conditions.

This shot has already had both contrast and sharpness boosted in post-processing. It's taken at ISO 100 with a K20D, handheld, at 1/320s, and probably stopped down to f/8. (I don't remember for sure, but given the "Sunny 16" rule adjusted for the late-afternoon hour, it's probably about right.)

The uncropped-and-scaled shot is first, followed by a 100% crop of a region near the center, and a 100% crop of the bottom left corner. Details are pretty visible, though a bit blurred, in the center; in the corner things get rather sloppy.

I'm curious how this compares to your results using that lens.

First up, the processed (but uncropped) original:



Close-to-center crop:



Corner crop:



11-30-2010, 02:08 PM   #9
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If you don't pixel peep those images look very good!

I've had a lot of back luck with image stabilization on heavy, old lenses over 200mm. I wonder if that shot would be a little cleaner in the corners with a faster shutter speed?

In either case, the whole picture looks great!
12-01-2010, 08:06 PM   #10
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Found Problem

The rear element need cleaning and the rear baffle was loose. I've been at my wits end trying to figure what was wrong with this lens. One didn't need to take a picture with the lens to see how blurry it was. Nothing would come into a reasonably focus. Out of frustration I borrowed a fiber optic scope to peer at the rear lens element. In trying to snake the scope through the rear baffle's doughnut hole the whole baffle turned cockeyed. It wasn't glued in place and turned sideways easily. However turned sideways the baffle let one see all of the rear element. Though the center was clean there was a grimy ring around the outside of the rear element. which one could not see because of the baffle. I cleaned the element and pressed the baffle into place. I then mounted the lens and took a look. The difference was immediate. The image finally looked sharp through the viewfinder. Test shots confirmed this (I had to put on a lens extender in order to focus close enough indoors)

Though I've been shooting with Pentax cameras (still have my Honeywell H1a) for about 40 years, I never run into something like this. I want to thank all of you for taking your valuable time to try and help me out. Hopefully I can return the favor.

Pete
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