cutting up a 2" L-extreme for use with a canon 6d

[powerlord]

I was wondering how easy it would be ? It'd be great to have a dual band filter I could easily use with my modified 6d and lenses.

I have UHS FF filter which I don't use, but could use that as a basis to make a 3d printed holder for a new filter, and use the size of it as a template for the new one.

I was then thinking I could try first with some cheap 2" IR filters, etc cutting out rectangles with a sharp cutter and snapping the glass. and then once I've got the hang of it, get myself a 2nd hand 2" L-extreme say, and cut a rectangle out it.

voila - nice FF dual band.

anyone done this ? is it in fact far far more difficult to cut a round but of glass into a rectangle than I am expecting ?

stu

[Ratlet]

Or you could buy some Stepdown rings and just mount the filter in the front of a lens like on most lenses.

[powerlord]

yeh I've tried that - it doesn't work well imho - you get massive amounts of vignetting which doesn't seem to be removed properly with flats. Plus I noticed with the 135mm at least, it seemed to do weird things to the back focus - whereas without filter I could get pin sharp stars edge to edge, with the filter on end of lens, all my stars at the outsides became horrible streaks. Plus it exposes the sensitive filter to dust,etc - I did think on the last bit to cover the filter with a UV one, but then that's more hassle and not really easy to stack filters.

Plus of course, the hassle of needing a precise set of stepdowns for every lens. I also wondered if putting it near the sensor might work better with wide angle lenses anyway re: angle of light incidence having to be perpendicular for NB filters to work.

Seemed to me, after the initial pain, it'd be much easier to use without all the faffing and should stop all the weird vignetting issues.

The elephant is - can it be cut really. I'll get a cheap IR blocker and give it a go.

[Elp]

To be honest I don't think this will work, camera sensor mounted filters tend to be thinner than the 1.25/2 inch variety so the light rays may not focus as a result.

It worked fine when I front mounted to my 200mm Takumar onto my Canon 600D and SY135mm EF adapted to Sony camera.

[powerlord]

well, if nothing else it sounds like a good experiment to stop anyone else doing it 🙂

 

[MalcolmP]

1 hour ago, powerlord said:

well, if nothing else it sounds like a good experiment to stop anyone else doing it 🙂

I was not sure if I should give you a "Smile " or a "Like" on that one
I do like a good experiment, [and reading about them ] !

So I got to thinking _
How you would support it while marking cutting and chipping, do they come with, or can you get protective films ? In which case could you use a carborundum or diamond abrasive grindy-wheel keeping all the dust off the bit that counts.
Then thinking outa da box - put it in a protective box! into which you have previously cut a narrow slot just long enough to allow the unwanted segment to protrude to meet its Dremel.

 
 

Edited August 30, 2023 by MalcolmP

[Elp]

If you've got access to a 3d printer it'll make mounting it a lot easier. Or just repurpose an existing one.

I think you can roughly check the focal plane distance before doing anything by pointing your lens at a light source focused at infinity stop (note theres plastic bits inside the SY) with filter behind and moving it to and fro from a wall or something and measure the backfocus distance, if it's greater than 44mm you won't be able to reach focus on the sensor. Might work, might not, but worth trying.

Edited August 30, 2023 by Elp

[powerlord]

as I said, I've got an optolong UHS FF clip in. Im gonna use that basically. I'll make a 3d mount based on it for the UHS one, but use the optolong frame with the new one. And use the UHS filter for the sizing.

I think easiest way to cut is to wrap in blue masking tape, then mark out the cuts on there, then cut.

then - experiment - as you say - one option might be a dremel cutter. another, a sharp diamond tile cutter thing then snapping once marked.

diamond scribe is suggested here:

https://www.cloudynights.com/topic/576628-very-thin-glass-cutting-techniques/

I've bought 150 microscope slides to practice on (if I need them all I think I should know when to quit) for 8 quid.

and a 4 scribes for a fiver...

Edited August 30, 2023 by powerlord

[michael8554]

Just checking you know that the mirror has to locked up before you insert a Clip-In filter in a Full Frame DSLR.

To prevent the mirror action being fouled by the filter.

Michael

[powerlord]

8 hours ago, michael8554 said:

Just checking you know that the mirror has to locked up before you insert a Clip-In filter in a Full Frame DSLR.

To prevent the mirror action being fouled by the filter.

Michael

yup, as I say, I've got the UHS one already. 👍

[powerlord]

Just an update - I got some slides and had a play. the <1mm ones are very easy to snap with a line on them, but these are definately thinner than an L-extreme (which I have managed to get second hand).

The thicker >2mm slides are trickier. they can be done the same way, but often don't snap right on the line and its then tricky to trim them.. I think I need to keep trying there.

Its tricky to score them all the way across at the start and end - I tried putting another one each side then scoring but its still not ideal. However for the 'real' rectangles, it will be 4 scores, and possibly scoring all 4 lines, then snapping will help to constrain the breaks to the lines. I've not tried dremels, etc yet. I mean, I'd rather not have to to be honest - glass dust everywhere is not something I really want on my hands, in my eyes. etc.

I will measure the thickness of the L-extreme I've got tonight, then do some more practicing.

I reckon IF they are close to the microscope slides or the cheap 32mm IR cut I got, I'll try to trim one to be the right size to fit in camera and test that lenses can still focus with it in there. My thoughts being if it does, then it should work with the L-extreme.

Obviously I want to be as sure as I can that this will work before I 'destroy' £160 worth of 2nd hand L-extreme. I do note that most clipins are 1mm, but that could be just for maximum compatibility - if it works with the lenses I want to use with my 6d then that's all I need - I'd imagine 2mm thick might just give me less wiggle room. We will see...

 

[powerlord]

Well..nearly a month later. Sorry about that. I got a bunch of microscope slides to practice cutting, then had to source second hand l-extreme..and finally work up courage to potentially destroy 2" l-extreme.

 

IT WORKED !!!

I have to finish it off a bit, fit a wee frame, etc but sticking it in to try it, all lenses I've tried have no problem focusing to infinity. So all looks good. Proof will be in pudding of actually trying it - I'll try sy135 first as never had good results with it mounted on front.

Here's a bunch of piccies showing me taping it up, scoring it with cutter. I found best way is to just keep scoring and eventually it just splits.

It's a bit bigger than the optolong, which moved about a bit.i plan to laser cut from 1mm balsa and 3d print something and see what works best for a frame. I've also blackened the edges of the glass.

So..no issues with focus, cuts OK, etc. For 150 quid I've got probably the world's only full frame clip in L-extreme. 😁😁😁

[powerlord]

Here's the finished article. I made a 3d printed frame in the end.

 

[powerlord]

First Light - IT WORKS!!!!