XL2 Mini35

[Rabi Syid]

I will be shooting a feature in February hopfully with XL2s and "Homemade Mini35" devices. I have read most of the posts and it is still confusing, But i understand the basic premise. I've started this thread from scratch just for the Xl2. Hopefully we can all come togther and build something solid! I will be doing my homework in the next couple of days.

Please Contribute. I need to Dimentions of and Xl2 lense front.

[Steev Dinkins]

I've been tweaking with a static adapter design for over a month now for my XL2. I've just finished documenting it on my website at:

http://www.holyzoo.com/zoo_updates.php

So far the design is as follows:

1. 35mm M42 lens
2. Adapter to 55mm filter size
3. Empty 55mm filters as spacers.
4. +4 Closeup Filter
5. Thorlabs 1500 Ground Glass
6. 2 +10 Hoya Macro Closeup Lenses
7. Stepup adapter from 55mm to 72mm
8. 16X IS XL1 Lens
9. XL2 Camera Body

It requires zooming in past the 55mm rings, then focusing manually on the ground glass, and voila - 35mm look, basically. I'm not sure how the XL2 20X lens would behave.

I can see improvements being made on the static design by either using a high end focusing screen instead of ground glass, or adopting a microcrystalline element technique.

Outside of these two improvements, I think the static adapter's potential is exhausted, and one would have to go with a rotating/oscillating ground glass/focus screen design. I personally haven't even touched that design yet, so if someone has achieved this and has fairly exacting details on the design, that would rock.

[Dario Corno]

Wow, thanks, this is very usefull !!

Let us know if you can solve the "problem" of the ground glass... this is also getting me crazy...

[Rabi Syid]

Hey Steve

Is your AIM Hollyzoo. I would like to talk to you over the internet.

[Eugene Presley]

amazing work. I'm truly impressed.

[Dario Corno]

Just for being correct... Steev did u mean step DOWN filter...

How much did u pay for the 55mm to screw mount adapter ??

[Steev Dinkins]

Ah, yes, step-DOWN is correct. Man, the step-up vs step-down is still confusing. I've corrected this error on my web page. Sorry for the confusion. Also, my AIM name is "holyzoo" for anyone who cares to chat.

The 55mm to screw mount adapter was comprised of 3 adapters as one, that SRB came up with. The cost came to be about $70 shipped from UK to US. The parts seem to be a M42 to 49mm adapter, male to male 49mm coupler, and a 49mm to 55mm adapter. I will leave out whether they are step up or step down. I always get it wrong! :) This surely beats the $200 quote I received from a local machine shop to custom build a part.

Btw, I'm looking into Medium format Beattie screens as the focus element. I wish I could see if anyone else has used one with this kind of design. Focus screens let in way way more light than ground glass and I have a feeling that the grain is next to nothing based on my first tests with a Hasselblad screen.

[Dario Corno]

Dunno if someone already posted that, but i found this site that sells beattie screen, they also have grid free screens (I never found grid free glasses).

http://www.intenscreen.com

[Steev Dinkins]

Dario, yes that's the manufacturer that I'm talking about. You can buy them from BHPhoto.com and Adorama.com but I think they are special orders.

I've been emailing a sales associate at the parent company, reflexite, and found the follwing plain screens with no markings that are close to 2" diameter:

Mamiya 645, 1000S________ 2.185 x 1.61"

Mamiya C220________ ___ ___ 2.214 x 2.322"

Pentax 67________ ___ ___ ___ 2.914 x 2.324"

Rollei SLX & TLR__________ 2.453 x 2.186"

All of these are about $150 US each. Question is can they be modified to fit in a filter ring?

[Dario Corno]

And what about buying an oversized glass and then cutting it ?? Is there someone who knows if that's possible ??
They are anything but cheap! :(

[Joshua Provost]

Steve,

I'm just getting into 35m adaptors. Wondering where focus/aperture/zoom is controlled once you go into this? I am guessing that you lock the camcorder into focus on the ground glass plane, and also must focus using the 35mm lens? Can you get this down to a science so it doesn't take forever to set up shots?

Thanks,
Josh

[Steev Dinkins]

If you were to go the route I have, the procedure I'm finding that seems to work reliably is to zoom past the Vignetting of the 55mm rings, then focus all the way clockwise on the 16X IS lens. Then this should not be touched (easier said than done). From there, all focus is done with the 35mm lens.

Regarding exposure, you can stop down on the 35mm lens which will alter your depth of field, or stop down on the 16X IS lens which will preserve your depth of field and just prevent over exposure. The ND filter is a bit overbearing on the 16X IS, so I haven't used it much.

So, I wouldn't say it's a science, but an art, I suppose. I still think of this adapter as an experimental art tool, rather than a professional solution.

Besides the noticeable grain, I'd say focus calibration is the next biggest flaw with this "add-on" design. Using a fixed relay lens would be a better way to go. I'm just out of money to spend on getting an XL to Nikon adapter. I think that is a next step.

I'm hoping that a cost-effective solid solution comes to light from someone in the community here.

Any other XL designs out there??

[Joshua Provost]

What do I need to know to adapt this to other cameras? If the CCD size and focal length of the camera is different than the XL2, will this alter the setup?

I sort of look at these setups as two pieces. First, the 35mm lens to a focus plane. Second, getting the camera to focus on that plane.

In that regard, I'm wondering why there is so much distance between the 35mm lens and the ground glass? Isn't this usually a much shorter distance in most 35mm cameras?

Also, if the focus plane was further away from the camera lens, wouldn't you be able to eliminate one of the +10 macro lenses?

Sorry for the questions, but I'd like to help break this down into some basic formulas that could be adapted to a number of cameras.

[Steev Dinkins]

Joshua, the focal length of the relay lens will impact everything up until the ground glass plane.

Regarding the 35mm lens to ground glass distance, I compared it with an actual camera body, and it's a comparable distance, 43-45mm or so, which is approximately what is specified for an M42 lens. So I consider the ground glass to lens distance the simplest part of the equation.

Regarding distancing the focus plane from the camera lens to eliminate one of the +10 macro lenses. I tested it (I know - I need a Test Chart):

http://www.holyzoo.com/111/xl2/35mm/images/1_Macro.jpg
http://www.holyzoo.com/111/xl2/35mm/images/2_Macros.jpg

I think it's a slight improvement with only 1 macro, but it adds 2" to the overall length of the adapter. I'd love to know how to easily get rid of the distortion.

[James Hurd]

Steev,
With just the macro on the camera, focus on some print that fills the whole screen. This should limit it to just the macro. It's possible that it's the macro. I use a DVX100a with a +10 hoya macro and mine looks distorted around the edges. I'm probably going to throw down the money for a century optics version.

http://www.sunrushmusic.com/micro35/micro35test.htm