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05-26-2011, 08:33 AM   #16
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QuoteOriginally posted by chicagonature Quote
I'm in Pentax's Professional Service program and I asked the rep about the claim that the backs can be converted. The answer is:
NO.

This should put an end to the discussion and speculation on this topic.
What would you expect them to say? First, Pentax would not want to take the liability of saying it is possible. Second, they would not want to do it.

05-26-2011, 09:15 AM   #17
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chicagonature, can you try and obtain the exact reasons why a conversion isn't possible? If the rep is a technical one who knows his stuff then this should be no problem. If it was a sales rep then he may be simply repeating what the company line is as others have said.

We have at least three users here who have done the conversion successfully so it can be done. The question that remains is whether the conversion may have long term detrimental affects to the insert or affect the focus or even the neg spacing. It would seem from the users that they have seen no adverse effects on focus or neg spacing and I cannot think of what part of the insert might suffer from longer term damage or excess wear and tear from the conversion but the rep should be able to point to this straight away.

Pity he seems to have thought that a one word answer of NO was sufficient. Whatever you can do to get reasons as to why it is not possible or advisable to convert with reasons will, I am sure, be greatly appreciated by all here

Thanks


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05-26-2011, 10:24 PM   #18
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The rep was talking about the details for a couple of minutes and it all became a blur. He seemed to know a lot about it and his final answer of "No" was fine with me. I just sent an email to get the reasons in writing, so we'll see. Don't expect an answer from me, though. I just thought I'd help you out because I know someone on the inside and ended up getting involved in something that I'm truthfully not that invested in. Personally, I'll just buy 120 inserts. It's not like they cost very much. I just thought that an answer from the manufacturer's expert would be good enough. I didn't think there'd be a conspiracy theory. Grassy knoll?
05-27-2011, 06:20 AM   #19
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Thanks for the response and initiating an e-mail to obtain reasons. The responses I am sure weren't an attack on you, the messenger, who was only offering what you percieved to be a helpful and authoritative answer from an expert which as you will have gathered is contradicted by some users' experience at conversion.

By the way the evidence seems to point to 120 inserts being much more expensive than 220 on both sides of the Atlantic. If a conversion is easy and safe then I am all for we P645 users saving money.

If the difference was a only few pounds or dollars I don't suppose many of us would be interested except on a sheer engineering curiosity basis.


asahijock

05-27-2011, 04:17 PM   #20
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Hi Asahijock,

Here's an email answer from my rep from Pentax today:
Our shop never offered any such “conversion” and always indicated that the appropriate film holder must be used to match the film length. (If “users” are making their own conversions, we’re not aware what they are or what detrimental effects would result).


I suppose you're still on your own.


Good luck!
05-27-2011, 04:37 PM   #21
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As I detailed before, the film length logic is taken care of by a simple mod.

Since then, I've learned some about film flatness - and how it may be compensated for by pressure plates and film channels. Although there doesn't seem to be a difference, there may be in the physical characteristics of the two inserts, i.e. a fraction of a mm may be difficult to notice, but may make a diff in sharpness.

Obviously, the film plane itself isn't different.

And at any rate, why speculate? If you have a 220 insert, try it, and report back! What's to lose?
05-28-2011, 09:34 AM   #22
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Thanks chicagonature for the Pentax quote. It mentions "our shop" This might be a shop as in a technical shop but it might be a shop as in a retail outlet. Certainly the quote suggests to me that this is not an answer from a technical expert/ camera engineer in a workshop. It still fails to give the kind of explanation I'd expect to get from an expert who gets faced with a "why not?" question.

Pity. If it is from the technical dept of Pentax itself then it undermines its credibility. Pity again.

Thanks again for trying. That's all you can do.

asahijock
05-29-2011, 05:46 PM   #23
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QuoteOriginally posted by Nesster Quote
As I detailed before, the film length logic is taken care of by a simple mod.

Since then, I've learned some about film flatness - and how it may be compensated for by pressure plates and film channels. Although there doesn't seem to be a difference, there may be in the physical characteristics of the two inserts, i.e. a fraction of a mm may be difficult to notice, but may make a diff in sharpness.

Obviously, the film plane itself isn't different.

And at any rate, why speculate? If you have a 220 insert, try it, and report back! What's to lose?
You are right, a comparison is needed. I can see no difference - and actually, do not expect any, as changing the middle part's direction actually does fool the 645 in thinking a 220 is a 120 - but if there's a difference in pressure, it should be obvious from a controlled comparison. Alas, I am about to move, which means my screen cezanne scanner has been stored away since January, likely to last to August, but when I'm back to normal I will certainly try. Frankly, the Pentax rep's comment is clearly non-informative, but there may still be an issue and we should find out

06-05-2011, 11:44 AM   #24
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220 insert to 120 conversion

I sent this out a while ago in reply to another query.

It is very easy to convert the 220 inserts to use 120 film. All it takes is a jeweller's phillips head screwdriver and a few seconds. Don't lose the little screw! Here're instructions, courtesy of another member:

"- mikebob -

I am and experimental physicist - I had to try .... and ... it works !!!

In the second link you have provided is a detailed description, but let me put my version here (I checked it twice!):

So - when one takes out the back and looks between the latches that can be flipped out to load/remove the film spools - there is a little black plastic rectangular of size about 12 x 4 mm. On one of the long sides it has a small tooth. This little "thing" is attached by a small screw. One of these screws is slightly obscured by the steel teeth that holds the film insert attached to the camera. When I have bought the camera with the 220 magazine, the teeth was pointing towards the back of the camera (away from film plane) and was easy to overlook.

So - to find out how this should work I used 2 films to figure out (one would have been enough though)

1) with the "thing" in its original position (teeth pointing away from the film plane) I loaded one 120 film in the back and shot 20 exposures until the film went completely through the camera. Then the camera did a short winding attempt and showed "E" on the display, which I guess stands for Error.

2) Unscrewing the 2 small screws I turned the plastic "thing" such that the teeth was pointing towards the film plane. Loaded another film and shot exactly 16 frames. After that the camera wounds the rest of the film onto the reel and showed "End" on the display.

So - it seems that with the teeth pointing towards the film the camera (or towards the shutter when the magazine is mounted on the camera) expects 120 film. What remains to be checked is simply to shoot a film or two in this settings and see that everything is OK. I would guess everything will be fine

I do not expect a problem with the film pressure plate is this has a lot of space to move (much more than the one in my Roilleiflex T)

... now all of you will run to get those cheap 220 inserts ..."

Note: My 220 inserts have only one screw holding the "tooth," perhaps there was a running change. Nevertheless Mikebob's instruction worked perfectly. I've run several rolls of 120 through the "converted" insert and I can see no problems.

Of course you'll have to remember that you've made the conversion!
06-06-2011, 08:51 PM   #25
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I made a post on this, but it was probably on another forum







Just some visuals to help you out. Visuals help me a lot.
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