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Petri M42 adapter warning found
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PostPosted: Sun May 05, 2013 12:36 pm    Post subject: Petri M42 adapter warning found Reply with quote

Nothing definitive here as this remains a work in progress. Still, for benefit of others with Petri interest I wanted to post this old auction for the sake of providing you opportunity to read its warning, which I found illuminating:

Click here to see on Ebay

The photographic evidence is less than I would like. But I think the above auction is selling the same Petri adapter as this current auction:

Click here to see on Ebay

which does NOT, however, contain the same infinity focus warning!!

The Petri proprietary breech lock mount register distance is short. It's not as short as Hexanon, for example. But as you can see here it is shorter than M42:

http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html

These adapters are expensive. If I'm correct in the above (not sure), be warned they might not work as you would wish.


Last edited by guardian on Sun May 05, 2013 2:17 pm; edited 1 time in total


PostPosted: Sun May 05, 2013 1:35 pm    Post subject: Reply with quote

Well, shouldn't a little bit of thinking be left to the buyer too?
Why push all to the seller's side? If something isn't mentioned,
don't assume it is there and if in question, do ask...

I'm just waiting for someone to blame sellers for bad pictures.... Very Happy


PostPosted: Sun May 05, 2013 2:48 pm    Post subject: Reply with quote

kds315* wrote:
Well, shouldn't a little bit of thinking be left to the buyer too?
Why push all to the seller's side? If something isn't mentioned,
don't assume it is there and if in question, do ask...

I'm just waiting for someone to blame sellers for bad pictures.... Very Happy


Sure. Whatever you want is fine. I changed my OP because:

My interest and wish on this thread is to discuss Petri adapters . . . . . . not propriety.

My earlier wording was what we call a "throwaway" . . . it was not intended to bring response.

Now if you actually had experience with this particular adapter, well, that's where my interest lies!!

I know the Petri breech lock lenses can be adapted, by one means or another. Until I saw the warning I had had hope this adapter could get the job done non-destructively. Call me crazy, but I have a strong preference for a non-destructive approach. So the warning was, for me, rather a head kick. It was a disappointment.

Luckily, because of the high price, I had not yet bought one of the adapters. I call that good fortune.

Conceded: These are old, probably circa 1970's-1980's, adapters. Things likely were different then. And most were probably sold, back then, in local brick and mortar stores. So if you had a dissatisfaction, you just returned the item for a quick and easy refund.

But today, with eBay and with the Chinese presence in the (modern) adapter marketplace, it's commonplace for adapters to be designed for infinity focus. And when that's not offered the Chinese warn you. It's easier for them, I guess, than messing up their eBay reputation with lots of negative feedback.

To be honest, I found the first-referenced (closed) auction entirely by accident. I'm glad I did, and that's why I posted it, in hope others with interest in Petri lenses and adapters would be helped as I was. I like the Petri lenses. I'd like them better if adapting them was more straightforward. Sad


PostPosted: Sun May 05, 2013 3:46 pm    Post subject: Reply with quote

I have no axe to grind here but wonder whether the Petri register was actually shorter than that for Pentax. I say this because back in the 1960s I recall selling Petri made adapters for M42 lenses that did - so far as I remember - permit infinity focus. The only problem I remember was that some M42 lenses were too wide actually to fit within the Petri cameras' locking collar. It may be that the Petri adapter was recessed to allow for a shorter register, but I can't remember if that was so.

Just to be clear: the adapter I'm talking about was to enable M42 lenses to go on Petri breech-lock bodies, NOT the other way round.


PostPosted: Sun May 05, 2013 5:17 pm    Post subject: Reply with quote

scsambrook wrote:
I have no axe to grind here but wonder whether the Petri register was actually shorter than that for Pentax. I say this because back in the 1960s I recall selling Petri made adapters for M42 lenses that did - so far as I remember - permit infinity focus. The only problem I remember was that some M42 lenses were too wide actually to fit within the Petri cameras' locking collar. It may be that the Petri adapter was recessed to allow for a shorter register, but I can't remember if that was so.

Just to be clear: the adapter I'm talking about was to enable M42 lenses to go on Petri breech-lock bodies, NOT the other way round.


Understood and agreed. The issue at hand here, though, is the other way 'round. To wit:

There are Petri MF lenses on the market today of decent quality at fair prices. These lenses have proprietary Petri breech-lock bayonet mounts. The adapters, links to which I posted in the OP, are able to adapt these Petri breech-lock mount lenses to M42 cameras.

It is not the subject of this thread, however:

Adapters allowing M42 mount MF lenses to mount onto Petri cameras do exist and are being offered for sale on eBay. M42 register distance being the larger (see link in OP), I would anticipate these adapters do allow infinity focus, just as you suggest.


PostPosted: Sun May 05, 2013 6:31 pm    Post subject: Reply with quote

The Ppetri bayonet and the m42 are almost the same flange focal distance 45.5mm and 45.46mm respectively. But the Petri bayonet (breechlock) must stand away from the m42 body because an adapter must have a finite thickness, so infinity can never be achieved however you do it and however the seller sells his goods it simply can't be done.

If you hold a Petri lens against the throat of an M42 body you will get approximately infinity focus, the petri lens is just a little too far forward, add about 1.5mm for a flange then it gets worse, but the Petri had a breech lock system which seems (by the looks of it) to be about 5mm thick. You have to add that too.

Not a chance in hell, and unless you are prepared to take off the mount and replace it with another (home made) it's not going to happen.


PostPosted: Sun May 05, 2013 7:53 pm    Post subject: Reply with quote

philslizzy wrote:
The Ppetri bayonet and the m42 are almost the same flange focal distance 45.5mm and 45.46mm respectively. But the Petri bayonet (breechlock) must stand away from the m42 body because an adapter must have a finite thickness, so infinity can never be achieved however you do it and however the seller sells his goods it simply can't be done.

If you hold a Petri lens against the throat of an M42 body you will get approximately infinity focus, the petri lens is just a little too far forward, add about 1.5mm for a flange then it gets worse, but the Petri had a breech lock system which seems (by the looks of it) to be about 5mm thick. You have to add that too.

Not a chance in hell, and unless you are prepared to take off the mount and replace it with another (home made) it's not going to happen.


Yup. Course only mount under discussion here is the Petri breech-lock bayonet. I acknowledge existence of the other Petri bayonet, which is akin to PK. Just not discussing it here, and the two eBay auction references in the OP are to the Petri breech-lock bayonet, as well.

None of that invalidates your point, which I take and appreciate. For me, personally, it's a little bit better. I'm wanting to adapt the Petri lenses for use on a camera with a (Sigma) SA mount. SA register distance is less than M42, which is a blessing. If I end up having to modify the Petri lenses (just bought my fifth) I hope I can do so reversibly and non-destructively. It would gnaw at me havin' to cut 'em up. It just would not feel right.

ETA

Just for clarity, here are the register distance numbers I am using. These are from the reference in the OP. If these are erroneous, well, I'm "up the creek":

Petri bayonet breech-lock: 43.5

M42 screw: 45.46

Sigma SA: 44


PostPosted: Sun May 05, 2013 9:54 pm    Post subject: Reply with quote



PostPosted: Sun May 05, 2013 10:27 pm    Post subject: Reply with quote



PostPosted: Sun May 05, 2013 10:43 pm    Post subject: Reply with quote

I leave a reply and blank??


PostPosted: Sun Jan 20, 2019 3:38 pm    Post subject: Reply with quote

Hi everybody,i'm looking forward to adapt a Petri breech lock mount 55mm 1.8 yo Sony A7, is there any cheap way to do it,i mean an adapter that i could buy? If not, i thought about a sony to leica helicoid + m42+Petri , but this shoudnt be to nice....would it be ok just to replace petri mount and glue a pentax k mount to it?


PostPosted: Sun Jan 20, 2019 3:59 pm    Post subject: Reply with quote

kiddo wrote:
Hi everybody,i'm looking forward to adapt a Petri breech lock mount 55mm 1.8 yo Sony A7, is there any cheap way to do it,i mean an adapter that i could buy? If not, i thought about a sony to leica helicoid + m42+Petri , but this shoudnt be to nice....would it be ok just to replace petri mount and glue a pentax k mount to it?

Here you are Click here to see on Ebay


PostPosted: Sun Jan 20, 2019 5:31 pm    Post subject: Reply with quote

If the adaptar is coming from USA , the price in Europe ,including customs will be around 90dollars, not very cheap option for a lens that who knows if it would be worth Sad


PostPosted: Sun Jan 20, 2019 5:45 pm    Post subject: Reply with quote

45+6+customs=90 ?!


PostPosted: Sun Jan 20, 2019 8:00 pm    Post subject: Reply with quote

45+6+30% (taxes) + 25 fee that is charging the shipping company for all the import taxes and papers,unfortunately ,buying from States is increasing too much the low amount a product might be worth