[GibbyTheMole]

Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here.

---

Can't help but wonder what the problem is with making a CS adapter for the Q. Is there a technical reason it would be impossible or impractical? I would think they'd sell like hotcakes, since CS lenses are dirt cheap and plentiful. I've even e-mailed Fotodiox on this idea, but received no reply.

I've toyed with the idea of using locking body caps as a homebrew CS adapter on a per-lens basis for some lomo-type applications. Thoughts?

[NeilGratton]

Unfortunately CS would require the back element of the lens to be impractically close to the sensor if mounted on the Q.

So, you either have the CS mounted back inside the body of the camera, or you have a lens that's impossible to focus at any distance.

Shame, really.

[GibbyTheMole]

Ah... I see... Another member successfully adapted a CS wide angle by boring out the hole on a D-mount adapter & gluing the lens to the adapter. It focuses properly, but I suppose it could be a fluke that it works with just that one particular lens, I dunno.

[drougge]

I've made several body cap adaptations of CS lenses. There are lenses where it doesn't work, because part of the lens hits the electrical contacts in the mount. Never had a problem with the rear element itself though, it's always possible to remove a little material from the lens and it works. Having a proper adapter to mount it in would be nice even in the case when I have to remove some of the lens.

I suspect the reason they don't make it is because it wouldn't work in m4/3 (they still have shutters, and CS lenses tend to be very close to the sensor when focused at infinity). (And our Q adapters are spin offs of m4/3 stuff I think, much bigger market there.)

[GibbyTheMole]

I've made several body cap adaptations of CS lenses. There are lenses where it doesn't work, because part of the lens hits the electrical contacts in the mount.

I'm thinking it might be fairly easy to tell which are the problem lenses by looking at a pic of the rear of the lens. Lenses with a smaller diameter rear end would be preferable to wider diameters that could hit the contacts.

How much time is involved in doing a cap-adapter. Is it worth the effort?

[hnikesch]

My CS 2.5mm does hit the contacts but I have not seen any issues because of it. Might be that it is flat black and might not be conductible??

Hans

[GibbyTheMole]

My CS 2.5mm does hit the contacts but I have not seen any issues because of it. Might be that it is flat black and might not be conductible??

Hopefully the paint doesn't wear off in that spot & cause a short. I've seen the results from your 2.5mm lens. Cool & cheap!

it's always possible to remove a little material from the lens and it works.

Dremel?

---

Last edited by GibbyTheMole; 02-19-2013 at 10:33 AM.

[drougge]

I'm thinking it might be fairly easy to tell which are the problem lenses by looking at a pic of the rear of the lens. Lenses with a smaller diameter rear end would be preferable to wider diameters that could hit the contacts.

How much time is involved in doing a cap-adapter. Is it worth the effort?

It's kinda hard to know how far they need to screw in from a picture though.

Certainly I found it worth the effort when the lens was decent. If you're used to doing this kind of thing it probably takes no more than 5 minutes, maybe 20 when you're me (plus time for the glue to harden). Longer if you need to modify the lens of course.

My CS 2.5mm does hit the contacts but I have not seen any issues because of it. Might be that it is flat black and might not be conductible??

Shorting the contacts is no problem, my dremeled lens still does that, but before it wasn't possible to mount it at all. (Unless I glued it on further out of course.)

[GibbyTheMole]

Certainly I found it worth the effort when the lens was decent. If you're used to doing this kind of thing it probably takes no more than 5 minutes, maybe 20 when you're me (plus time for the glue to harden). Longer if you need to modify the lens of course.

Yeah, I'll probably pick up a super cheap CS lens & try my hand at it. Something to keep me busy for a little bit, anyway. :-)

[digital029art]

I've tried a different approach using a plastic twist in body cap + one of those aluminum threaded CS->C adapter rings nested inside. After drilling, shaving & filing it's pretty close. I still need to shave off close to a mm, at which point the only part left of the donor body cap will be the just (plastic) Q mount claws ..lol - I wanted to have a reusable CS->Q adapter .. it may still work.
Hardest part is perfect centering and flatness of the plane, so I'm gonna try shaving with a wood planer since I don't have access to a lathe.

One other main thing to consider also is that many if not most CS lenses are for like 1/3" sensors or less so there will be vignetting for sure even on the Q .. though I do like the really small & light form factor of CS lenses!

[hnikesch]

Yeah, I'll probably pick up a super cheap CS lens & try my hand at it. Something to keep me busy for a little bit, anyway. :-)

That's why I did mine, I wanted to play rather than just return the lens. What other camera can you build adapters for and succeed. That's part of the fun of the Q

Hans

[Erich_H]

I've toyed with the idea of using locking body caps as a homebrew CS adapter on a per-lens basis for some lomo-type applications. Thoughts?

I've tried my first board mount lens on my Q. This f2,0/2,1mm lens cost me US$ 7:-.
This lens is built to cover an 1/3" security camera sensor, so it will vignette on Q.
The color rendition is all over the place and the lens is softer than cotton candy.
The color aberration is also due to my leaky, melt glued impromptu adapter made out of a milk carton cap...
but the results are fun and I'm going to build a (hopefully) less leaky, more permanent adapter (body cap)
when I get around to it. So, please look at these more as "proof of concept" than serious pics!
The LOMO factor is assured! With this method you'll be able to test the CS lens before you
commit an expensive body cap to the experiment!

Pics 1 and 4 are center crops.
Pics 2 and 3 are uncropped with all the optical aberrations you'll ever want...

Pic 0 - impromptu adapter




Pic 1 - Center crop from RAW file




Pic 2 - Bold Monochrome on front dial




Pic 3 - Brilliant Color on front dial




Pic 4 - Center crop from RAW file




Thanks/Erik

[drougge]

The color aberration is also due to my leaky, melt glued impromptu adapter made out of a milk carton cap...
but the results are fun and I'm going to build a (hopefully) less leaky, more permanent adapter (body cap)
when I get around to it.

I would suggest a two step approach:

• Buy this lens (or another much like it) and glue that to you lens cap. It's a decent lens too, so it's worth doing either way.
• Then when you want to mount your board mount lens you unscrew the front of this lens, which leaves a board mount hole (and a spring that falls out). Screw your board mount lens in.

This gives three advantages:

• An extra 2.8mm lens.
• A way to focus your other board mount lens (making decent threads in a body cap is hard).
• Makes it easier to mount it straight. (The back of the CS adapter the 2.8mm lens comes in can go flush to the body cap.)

Not all board mount lenses work though, I tried it with one that hits the beveled edge around the sensor before reaching infinity focus.

[Erich_H]

I would suggest a two step approach:

• Buy this lens (or another much like it) and glue that to you lens cap. It's a decent lens too, so it's worth doing either way.
• Then when you want to mount your board mount lens you unscrew the front of this lens, which leaves a board mount hole (and a spring that falls out). Screw your board mount lens in.

This gives three advantages:

• An extra 2.8mm lens.
• A way to focus your other board mount lens (making decent threads in a body cap is hard).
• Makes it easier to mount it straight. (The back of the CS adapter the 2.8mm lens comes in can go flush to the body cap.)

Not all board mount lenses work though, I tried it with one that hits the beveled edge around the sensor before reaching infinity focus.

Thanks drougge! I'm close to your solution. I know that I am talking about board lenses and not CS, but I think a lot of this easily transfers to CS....
I was going to use a metal board lens holder (price 70 cents), saw off the round threaded part and glue that inside the body cap after making the center hole.
Then it also will be easier to get the focus plane of the lens and the sensor in parallel.




I also managed to get some passable results (Toy Cam Style) when I saw to it that the lens was tilted not so much and centered over the sensor a little bit.
Still with the same glued adapter though... first pic w/high contrast filter in Q, second pic just developed in mono from RAW, both with extreme edge cropping. The edges are really LOMO....







Regarding CS, I was more thinking of one lens per body cap as per hnikesh recipe below,
but with a body cap instead of D-adapter.... https://www.pentaxforums.com/forums/pentax-q/211126-cctv-2-5mm-cs.html

Thanks/Erik

[digital029art]

Finally found an actual CS->Q adapter from Taiwan. Downside: it's $50 !

http://digitalhobby.biz/products/detail.php?product_id=87