Use of 2x converter with various lenses.

I'm getting pretty close to picking up my 67II system. I have a few more questions regarding the 2x converter.

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Basically the system I'll be getting is as follows and I need to know if the 200mm lense with its closer focus can be maintained with the 2x coverter in place. I really wanted the 300mm until I saw that the closest focus was around 16 ft.

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Pentax 67II body

AE Pentaprism

105mm lens (I like the fast aperture and the compact design)

55-100mm zoom lens

165mm leaf-shutter lens

200mm lens <OR> 300mm lens [non ED(IF)]

Auto-Extension tube set

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NOTE - 300mm ED(IF) I don't have any pricing for, but it's probably out of my price range. If anyone has pricing info, let me know.

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Now here are the questions:

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1.) How good is the 2x converter, image and build wise.

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2.) Can the 2x converter be used with all of the lenses mentioned above, especially the 55-100 zoom, and what kind of performance can I expect on the lenses mentioned above? What kind of performance on the 55-100 zoom? What kind of performance with the 165mm LS lens? etc, etc.

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3.) Can the auto-extension set be used in conjunction with the 2x converter to give twice the working distance in macro mode? I ask this specifically for the 105mm and 165mm LS lenses as they'd probably be the only lenses I'd use the auto-extension tube set with.

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On to another non-lens related question. I know that NPC makes a conversion for a polaroid back for the 67II. But has anyone ever tried to order a plain back from Pentax and mate this to one of Polaroid's 545i sheet film backs? I suspect with some modifications and some specific machine shop work something could be made for less than the $700-800 that NPC charges. Fiber optic cable bundles are really not all that expensive anymore, but I was thinking something a bit easier, like a custon mount for the Polaroid back to the Pentax back without the fiber optics. The only hard part would be getting the film in the correct plane of focus, but since it's a Polaroid used to check composition and maybe exposure, I don't think this would be too critical of an issue, a bit fuzzy wouldn't bother me, since the Polaroids aren't really as good a chromes anyhow. Any ideas?

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Regards

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S Ratzlaff

Wow, that didn't format correctly.

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The equipment should read as follows:

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Pentax 67II body;

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AE Pentaprism finder:

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105mm lens;

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55-100mm zoom lens;

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165mm leaf-shutter lens;

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200mm or 300mm non-ED(IF) lens;

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Sorry for the formatting issue.

I cannot answer all your question but I can provide some information:

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Pentax does not recommed using the 2x converter with the 55-100mm zoom

or the 165mm LS lens. A combination of extension tubes and converter

should be possible in principle but I have some doubts about the

resulting image quality.

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The new 300mm ED lens has an improved close focus distance (2m) and

sells for 1600 USD at Cayman Camera according to earlier information

in this forum. However, due to its non-conventional design (IF), 2m

sounds better than it is in terms of magnification. The lens reaches

only 1:5.6.

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From the set of lenses you mentioned I would chose the 200mm lens

in combination with an achromatic close up lens for close up work (up

to 1:2, say; not for extreme magnification). My experience with a

similar combination (2.8/165mm + Pentax T132) at 1:4 is very good.

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Regarding a NPC substitute I have no idea.

The 300 EDIF can be had from Cayman Camera for around $1670. Some of

your questions about the 2x converter and lens performance can be

found in other parts of this forum. The 165 LS is a good choice

because of its f/32 DOF and its Ernostar design(same as the 200

Pentax). But, to buy the 165 and 200 you might find them to be too

similar in magnification. The use of converters is a mixed bag. For a

converter to have optimum performance, it should only be designed for

one lens(ie the 1.4x on the 800ED). Trying to push converters to other

focal lengths compromises performance. IMHO I feel the use of a 2x

on any zoom is mistake mostly because of contrast issues due to the

total number of elements(17+) involved but also because zooms by

nature will have sweet spots and weak area of performance. These weak

areas will be aggravated by the converter.

Using a 2x converter to increase your macro standoff distance is

questionable because you could easily use a higher magnification

lens instead. The 200 works well in macro situations. SR