[oscaletrains]

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How exactly would this work? I am thinking of the Canon EF 100mm f2.8 macro 1:1 lens here...you cannot use the Pentax OEM adapter with aperature because there is no way to adapt a Canon EF lens to a P/K mount that I am aware of, but, you could use a China Q adapter for it easily enough. Now you have the issue of not being able to stop down the aperture so you are shooting at f2.8, which is going to be crap for DOF.

Ideas?

The only solution I have found so far is to mount the lens on a Canon body(wonder what the cheapest Canon body would be that could do it is) and in AV mode set the aperture to what you want, hold down the DOF preview button and remove the lens from the camera, which will cause the aperture to remain where it is stopped down to and then on the Q you will be stuck at using that aperture....but that would be better than wide open...

Looking for ideas here...

[oscaletrains]

Ok, no one has any ideas yet, so

I broke down and ordered the real Pentax adapter from B&H. That will take care of the aperture issue and I am sure i would have bought one eventually anyway. The trick now will be to attach a p/k mount from an old junk lens to the Canon EF lens. Obviously I will lose infinity focus...but hopefully gain an awesome macro setup.

[digital029art]

I don't see how the K mount adapter will help with stopping down Canon EF lenses, but it will work great for any K mount lenses you may have.
There's an alternative in the form of this style of adapter that has it's own aperture iris built in: New adaptor for using you Canon EOS lenses on GH1/ GH2/ AF101 | Philip Bloom

Maybe you can find an adapter like this to go EF->m4/3, or EF->Nex and then to C mount or Q mount. Not the cleanest solution, but then there are so many options for macro with the Q that you have to see if the EF lens is worth it!

[VisualDarkness]

You need an Eos body to work the correct aperture before putting the lens on the Q.

[oscaletrains]

I don't see how the K mount adapter will help with stopping down Canon EF lenses, but it will work great for any K mount lenses you may have.
There's an alternative in the form of this style of adapter that has it's own aperture iris built in: New adaptor for using you Canon EOS lenses on GH1/ GH2/ AF101 | Philip Bloom

Maybe you can find an adapter like this to go EF->m4/3, or EF->Nex and then to C mount or Q mount. Not the cleanest solution, but then there are so many options for macro with the Q that you have to see if the EF lens is worth it!

I was mistakenly thinking that the EF Cannon lens would behave just like a Pentax lens that has no aperture ring with the Pentax brand Q adapter...but crap, brain fart. I am back to setting the electronic aperture somehow or some way to fake an aperture in the adapter...crap.

---------- Post added 08-06-14 at 06:06 PM ----------

You need an Eos body to work the correct aperture before putting the lens on the Q.

Wish I knew which pins controlled the aperture and what voltages placed them in what position...

---------- Post added 08-06-14 at 06:09 PM ----------

New adaptor for using you Canon EOS lenses on GH1/ GH2/ AF101 | Philip Bloom

Now THAT is a possible, I would have to fit a p/k mount on the ass end of it, but that should not be too hard.

[johnmflores]

You must really want to use the Canon macro. Does it have pixie dust?

[lecoupdejarnac]

I've come across one adapter for EOS lenses, that has a built-in aperture:

New Kipon Adapter with Aperture for Canon EOS EF Mount Lens to Pentax Q Camera | eBay

It's a bit pricey though. I've considered buying it for a Canon-mount Sigma 70mm 1:1 macro lens I have.

[oscaletrains]

I've come across one adapter for EOS lenses, that has a built-in aperture:

New Kipon Adapter with Aperture for Canon EOS EF Mount Lens to Pentax Q Camera | eBay

It's a bit pricey though. I've considered buying it for a Canon-mount Sigma 70mm 1:1 macro lens I have.

Yea, that one is pricey...I looked on ebay for the regular iris ones and there are about 3 different versions of the same thing. One of them had a removable rear mount so I ordered that one to try to see if I can bolt a p/k flange on it. Either way, I guess I did not need to order the Pentax adapter, but oh well.

---------- Post added 08-06-14 at 08:06 PM ----------

You must really want to use the Canon macro. Does it have pixie dust?

That's what I want to know! But it DOES do 1:1 without an extension tube. Unfortunately what I am doing to mount it is like adding extension so no way will it focus to infinity, and it probably could not have anyway regardless of the what mount was used. Nothing ventured, nothing gained though.

---------- Post added 08-06-14 at 08:28 PM ----------

You need an Eos body to work the correct aperture before putting the lens on the Q.

Yea, wish I knew someone that was a canon guy around here. Can't see buying a body just to do that with though, that's no fun.

[barondla]

The adapter has a diaphram in it. Wonder what changes optically vs using the aperture in the lens?
If your EOS macro lens is full frame ( words rarely tolerated in Q forum), you could buy a cheap Canon film body to set aperture. Have seen them for $20 - 30. Just make sure the body has dof preview.
good luck
barondla

[VisualDarkness]

I couldn't find the great guide to lens designing I found earlier but Lenstip points to distortion atleast: LensRentals.com - The Seven Deadly Aberrations

"The position of the stop (aperture ring) in the lens can greatly influence the amount of distortion. In a simple lens, if the stop is near the lens, there is little distortion, but if it’s located far in front of or behind the lens, then distortion is more likely. Changing the position of various elements when zooming or focusing a lens in relation to the stop may increase or decrease the amount of distortion in that lens."

[oscaletrains]

The adapter has a diaphram in it. Wonder what changes optically vs using the aperture in the lens?
If your EOS macro lens is full frame ( words rarely tolerated in Q forum), you could buy a cheap Canon film body to set aperture. Have seen them for $20 - 30. Just make sure the body has dof preview.
good luck
barondla

Well, that was my first thought, but I didn't see any ebay Canon's that would do it that cheaply. IF this works though, I might also be able to use it on a regular K10 body also...?

---------- Post added 08-07-14 at 05:39 AM ----------

I couldn't find the great guide to lens designing I found earlier but Lenstip points to distortion atleast: LensRentals.com - The Seven Deadly Aberrations

We shall see!

[oscaletrains]

Here is what needs to fit together. The EOS Canon lens mount is slightly larger than the Pentax M size mount, and I have no way to control the iris in the lens. I could just get the adapter mentioned above and the lens would work with the Q, but then it would not work on my K10 or anything else, so the idea is to try to use the EOS to M4 3 adapter, attaching it to the lens, and then modifying the 4 3 end of the adapter to be a K mount instead of the 4 3. That way it should fit on a K10 also and be able to work in manual using the adapters iris, and hopefully work on the Q using a cheap non iris adapter in the same way. A donor lens has provided a K mount, so removing the 4 3 mount screwed onto the back of the adapter and fitting the donor mount to it will be the job necessary next.

IF it all goes south, I guess i will have to just be satisfied using it on the Q with the other adapter...

[oscaletrains]

Did it...

https://www.pentaxforums.com/forums/136-pentax-q/209474-adapted-lenses-tested...thread-56.html

Message 840 and following

[pinholecam]

IMO, I'd just spend the money for a vivitar 55/2.8 macro or vivitar/tokina 90, 105mm macro and be done with it.

[hnikesch]

Yea, wish I knew someone that was a canon guy around here. Can't see buying a body just to do that with though, that's no fun.

You could buy an old film EOS body on the cheap from ebay I have seen them for $10