Pentax 645 Zooms, Teleconverter

(cross-posted from rec.photo.equipment.medium-format on UseNet)

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I'm looking into a Pentax 645 system. I've searched archives of the Pentax mailing list and the Medium Format Digest, and have found useful information on most aspects of this camera (plus, recently, some interesting speculation about a next-generation 645 that might be intro'ed by Pentax in the near future). However, I haven't seen much discussion of the 645 zooms and teleconverter, so would appreciate user comments on them.

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1) Pentax 645 45-85/4.5

Pentax 645 80-160/4.5

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How have users found these lenses to perform (sharpness, contrast,

mechanics) compared to the 645 prime lenses? I'm especially

interested about optical performance at the smaller apertures (for

the tripod-mounted landscape work I do, DOF is often a concern for

me, and I rarely shoot wider than f/8 or f/11, using f/16 and f/22

most commonly). I understand both of these lenses stop down to

f/32...what is performance like at this aperture?

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(The archives I've searched did include a couple of comments about

zoom creep on both lenses, and vignetting of filters on the 45-85.

Any other info, or further details on these problems - eg, is the

creep consistent or a flaw with that user's units; how much

vignetting are we talking about; etc - would be appreciated, too.)

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2) Pentax 645 2x teleconverter

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What about performance of this teleconverter when matched with the

80-160 zoom (assuming it matches with the zoom - does it?).

Again, I'm interested mostly in apertures at f/11 and smaller.

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From the B&H catalog, it looks like Kenco (sp?) makes a

Pentax-compatible 2x teleconverter, too. Does anyone know about

this?

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Thanks for the info,

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Scott

I can only comment on the 80-160 zoom. The sharpness and contrast were excellent and the lens, in general, yielded excellent results. It is quite heavy and was tiring after a day of handholding. Also, there was some "creep" in my zoom ring when the camera was pointed down. It was negligable, but it was there. It might be worth hearing if others have the "creep" before assuming it is so on all of them. I don't know the age of the lens I had.

I recommend it but you should rent one first if weight is a concern for you.

Mike

I have been using the Pentax 80-160 zoom and the Pentax 2X converter. Contrast and sharpness of the zoom is superb and I find it comparable to the 75/2.8 and 150/3.5 lenses. Colors are excellent, a bit warmer than the fixed focal length lenses. Indeed the zoom is heavy, and its focusing ring does tend to creep under the weight of the front element when pointed down. However, Pentax service was able to fix the problem for me. The Pentax 2X converter works remarkably well with any lens in the P645 line. I use it with the 80-160 zoom and the 200/4 lens, and pictures come out razor sharp with excellent color and contrast. I don't believe third party converter could match the Pentax quality.

Good luck, Moshe