Using Pentax 67 lenses on Pentax 645? Please enlighten me....

[harlequin]

Hello Team,

Was out on SPI South Texas and witnessed individual shooting with pentax645 body but using 6x7 Pentax lenses.

Question s,

A) looked like a nice Pentax adaptor, however after paying for said adaptor, what are the advantages of doing this?

B) if you’re using a 150mm lens on P67, does it become a different focal length? If so what’s the multiplication?

C) every Pentax I have owned had good optics, and I am sure the 645 Pentax lenses are no slouch, other than expense and added weight of larger glass, what am I missing?

Thanks for your feedback and input on this, any image shot with 645/67 retrofit greatly appreciated!


Regards,

Harlequin

 

[wiltw]

The rated focal length is the rated focal length. The fact that a 150mm P67 lens is mounted via adapter to P645 body changes nothing, it is still going to present the same image that would be presented by a P645 mount 150mm lens.

The only advantage to mounting P67 lens on P645 is when you do not own that FL in Pentax 645 mount lens!

The ONLY use of a multiplier is to convert AOV...saying "If I mount 250mm FL from P67 onto my P645, the lens on P645 sees and AOV equivalent to (fraction) smaller FOV....like in FF vs. APS-C, 150mm lens on FF is like mounting a 90mm lens on APS-C...similar FOV is captured.

 

[MattKing]

I would guess that the 105 mm f/2.4 would be a nice short telephoto on the Pentax 645.

 

[Luckless]

If there aren't new glass elements in the adaptor, then it isn't going to change the focal length of the lens. So a 150mm lens on a 6x7 camera bends the light the same as it will for a 4.5x6 camera, and the same for a 35mm or smaller camera.

You'll crop out a different part of the image circle with a smaller sized camera, but that doesn't change how the lens itself it working. You're just recording less of the area.

'Crop factor' can be useful to roughly compare different lenses across different systems. So the 150mm lens on the larger 6x7 film will net you an angle of view similar to a 120mm lens on the smaller 645, but swapping the 150mm lens to the 645 camera will still give you a 150mm lens that will be similar to a 150mm lens specifically for the 645 camera.


If you go down the rabbit hole of converting lenses to different cameras than they were designed for then remember two key things:

The back of some lens designs are closer to the film/sensor than others of similar focal length - Be wary of smashing mirrors on SLRs. Some combinations 'work', but only at some focus distances, or only with the mirror locked up the entire time. Try to learn this lesson from others rather than learning it for yourself.

Image Circle: Using a lens from a larger format camera on a smaller format generally works well enough, barring issues with distance to the film, but lenses for smaller formats may not project a big enough of an image circle to be used with a larger format.

 

[MattKing]

Does a tilt/shift adapter permitting use of P67 lenses on P645 bodies exist? If so, that would add some useful capability.

 

[Luckless]

Does a tilt/shift adapter permitting use of P67 lenses on P645 bodies exist? If so, that would add some useful capability.

'Maybe'?

Poking around on google didn't come up with an actual tilt/shift version, but did spit out this: https://fotodioxpro.com/collections/lens-mount-adapters/products/p67-p645-p

Which is a pretty small direct adaptor. Not sure the flange distance difference between the 67 and 645 would leave much room for a tilt function without giving up some focus range.

[But loads of tilt shift options for p67 lenses to smaller/mirrorless cameras.]

 

[Oren Grad]

Does a tilt/shift adapter permitting use of P67 lenses on P645 bodies exist? If so, that would add some useful capability.

Zoerk Pro-Shift adapter, type ProSA-P67. Not cheap.

 

[DREW WILEY]

There are several reasons. A person might own both 6X7 and 645 camera bodies, and want an adapter for that reason. There also happen to be certain P67 lenses which are optically superior to the equivalent focal lengths in the 645 system. You'd also be dealing with just the center of the optic too, which often equates to peak performance even wide open.

But a tilt/shift adapter excuse is more like a Hail Mary pass, and would be rather clumsy in MF size. A real view camera will do the job far better and easier, and perhaps on a lower budget too. Pentax did sell wide-angle shift lenses for architectural use. Real view camera lenses are generally formulated with respect to greater image circles than necessary for ordinary head-on lens usage, and are better corrected for tangential light ray angles (relative to tilts and swings). In fact, the optical elements of the Pentax shift lenses were actually made by Schneider as a variation of their Super Angulon series.

 

[benveniste]

I can probably dig up some shots using a Pentax 67 300mm f/4 I picked up for silly money -- since there are no optics in the adapter it works exactly like a 645 crop from a 67 would. The Pentax 67->645 adapter works pretty well, including using aperture priority mode, but as usual, the reason to use a lens adapter is because you happen to already own some lenses, and you are willing to give up some convenience in order to save some money or room in your kit.

 

[DREW WILEY]

The 300/4 is decent, and really a bargain on the used market these days. But the 300/4 EDIF is an outright spectacular lens, so has retained its high pricing, I own both of them. Being heavy and difficult to stabilize, you need an especially solid tripod to get the best out of them, although at higher shutter speeds I've successfully shot them rife-style, resting on a folded jacket atop a car roof or fence post. I even have an excellent Nikon adapter for them - nice wildlife combination, although I'm only an opportunistic photographer of animals, and not a dedicated one. By needing only the center of the optic, using a smaller camera like either a 645 or 35mm, even shooting the lens wide open yields excellent results.

 

[itsdoable]

At one time I owned both the p67 and p645 v1, and I had the genuine Pentax 67-645 adapter. You could shoot the p67 lenses in full metered or AE mode, without stop down metering, and with auto aperture. It was nice for lenses you didn't have (yet) in the newer p645.

 

[johnha]

As mentioned, the operation of P67 lenses on P645 cameras with the Pentax adapter is seamless. You get metered manual and aperture priority open aperture metering with auto aperture. You only lose program, shutter priority and AF if applicable but get focus confirmation on AF bodies.

P6x7 lenses are very good to start with, you're not using the edges of the lens coverage and they're not much bigger/heavier. Many of the later lens formulas branded as '67' are really good - 55/4, 75/2.8 AL, 200/4, 300/4 EDIF and the two zooms 55-100 & 90-180.

I bought a 645D and only used 67 lenses on it for a while. The only limitation is wide angles as the widest rectilinear option is 45mm which isn't quite wide enough. I still mix the 645D and P67 bodies using a mix of 645 & 67 lenses: 645 FA33-55, 67 55-100 and either the 67 90-180 or 67 200/4. The 6x7 90mm f/2.8 leaf shutter also works seamlessly with/without the L/S, syncing at up to 1/500th on the 645D.

 

[yurihuta]

Zoerk Pro-Shift adapter, type ProSA-P67. Not cheap.

Used one can be had, just send me a private message. It is really beautifully made.

 

[yurihuta]

...or if you want a faster lens like the simply superb SMC Pentax-M* 67 400mm F4 ED [IF]. The best in a native 645 mount is an F5.6.

The only advantage to mounting P67 lens on P645 is when you do not own that FL in Pentax 645 mount lens!

 

[DREW WILEY]

.... or the 300 EDIF. Or if you want to use only the center of the optic of something fast like the 105/2.4 and get superior performance even wide open. So that same axiom might very well amount to realistically shooting one of the 6X& EDIF teles at f/4
on a 645, whereas even at f/8 you might not get equal performance with a 645 tele. Those EDIF 6X7 teles are so well corrected that they were prized by widefield astro photographers even for 35mm use.

 

[Randy Stewart]

The Pentax adapter allowing use of P67 lenses on the 645 models is fukky described above.; The only reason to use it and 67 lenses on a 645 is if you already own a bunch of 67 lenses and want to use a 645 without buying a whole new 645 lens system. There are no other advantages.;The adapter does not fully enable the metering options of the 645. The 67 lenses, being designed for a much larger format than 645, are going to be in any focal length slower, larger, heavier, and have some bit less optical performance. If you do not need to buy lenses for a parallel 67 system, the 645 lenses are generally less expensive. I have full P67 system with several bodies and many lenses. If I were going to fully change over to a 645 system, I'd sell off my P67 system in full and buy Bronica Etrsi system to replace it.; Over 35 years, I considered the Pentax 645 as an option, but I cannot get around its lack of mid-roll interchangeable film backs. The Bronica is currently selling at relative bargain prices.

 

[Matteo_Csepeli]

Used one can be had, just send me a private message. It is really beautifully made.

Hi yorihuta! If it's still available I will buy it for sure! I'm struggling to find one, and admit I joined the site because of this post.

 

[MattKing]

Used one can be had, just send me a private message. It is really beautifully made.

Hi yorihuta! If it's still available I will buy it for sure! I'm struggling to find one, and admit I joined the site because of this post.

Matteo_Csepeli is most likely not yet able to initiate private messages, due to his low post count.
But if you wish to initiate a conversation yurihuta, he will get an Inbox notification, and will be able to respond and continue the discussion afterwards.

 

[Matteo_Csepeli]

Matteo_Csepeli is most likely not yet able to initiate private messages, due to his low post count.
But if you wish to initiate a conversation yurihuta, he will get an Inbox notification, and will be able to respond and continue the discussion afterwards.

Thank you for your kind support! Looks like a nice place here!

 

[MattKing]

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