Veil with CCD and old camera lens

[Stardust]

This started of as an experiment just to see if I could get the lens focussed, wasn't expecting much but pressed on to the early hours of Sunday as the data was looking worth while.

It was only HA 8 x 600 OIII 8x800 then the clouds came in and have stayed, I'd liked to have spent more time but at least the test shows promise. 

Atik One with a Carl Zeiss 135mm M42 screw lens f4

I'd like to see results from a lens on an Atik 314L+ as i'm thinking of acquiring a second hand one to put on the rig.

Feel free to add images if you have them

thanks for looking

[xtreemchaos]

a great image mate,lovely detail,well framed.thanks for sharing.charl

[m.tweedy]

i have one of those lenses. how did you attach it to the Atik as i have a 460ex.

thank you

[JamesF]

That's certainly come out rather nicely.

James

[m.tweedy]

i never thought of attaching any of my lenses to the CCD

[Kropster]

Did you use the lens wide open or stopped down?

There seems very little distortion.

Maybe the CCD is just taking the central part of the image the lens produces?

p.s. lovely image!

[michael.h.f.wilkinson]

Superb. Really shows that old lenses can produce real quality shots

[JamesF]

There are adapters that will take a (for example) Canon EF lens and allow it to be fitted to a camera with a T2 thread.  Geoptik make one, but it's not cheap.

I'm not sure that's what the OP has done though.  A T2 mount is M42 as his Carl Zeiss lens appears to be, but as far as I recall the Zeiss thread is M42x1 (same as the Pentax thread) and T2 threads are M42x0.75, so I'd be interested to know how he did it.

James

[m.tweedy]

in my excitement of seeing this image and how it was taken i forgot to say that i like it a lot

[m.tweedy]

Thats exactly why i am interested in the answer James

[Stardust]

thanks guys, as it happens I had an adaptor but sure they are available, you need a M42 camera thread to T2 thread. They are the same size but a different pitch. Uses spacers or extensions tubes on either side to get the spacing about right. I didn't expect it to work quite so well. 

[Stardust]

Did you use the lens wide open or stopped down?

There seems very little distortion.

Maybe the CCD is just taking the central part of the image the lens produces?

p.s. lovely image!

I only stopped it down one click, it's a f3.5 lens so guess that is around f4. I was expecting distortion in the corners at least but there's no cropping on this image. I did try a 35mm lens which was terrible 

[JamesF]

I only stopped it down one click, it's a f3.5 lens so guess that is around f4. I was expecting distortion in the corners at least but there's no cropping on this image. I did try a 35mm lens which was terrible 

What you can do if you're not keen on the diffraction spikes created by the vanes when you stop down is to cut a circular aperture mask to fit to the front of the lens instead.  Or they might not bother you   I like my stars to look like stars, not starfish

James

[Stardust]

yes good idea, I may not need to stop this one down as it was only a fraction. They hadn't bothered till you pointed it out   

[JamesF]

Sorry

I bought some sheets of thin black plastic sheet and a disc cutter off that ebay.  An idea I shamelessly stole from Olly, I believe.  The one I bought is like this: http://www.ebay.co.uk/itm/Compass-Circle-Cutter-Cuts-Perfect-Circles-Hole-Paper-Vinyl-Card-Craft-Leather-2-/321555584199

It's an amazingly useful piece of kit when you have one.  I've even been using it recently to cut bespoke seals from silicone sheet for the fittings on my new stainless boiler for the brewery

James

[Stardust]

no worries, helpful hints are always welcomed. I'm sure I've got one of those cutters somewhere, now for some thin plastic sheet.

David

[m.tweedy]

thanks guys, as it happens I had an adaptor but sure they are available, you need a M42 camera thread to T2 thread. They are the same size but a different pitch. Uses spacers or extensions tubes on either side to get the spacing about right. I didn't expect it to work quite so well. 

thank you

[Stardust]

This was the only other image I managed, 1x10 min lum, just to show the field. There is vignetting on the corners, this was with a Canon 100mm f2.8 macro lens

should have been in HA but set the wrong filter number blooming shame as the unsaved screen shot looked looked really nice. The Crescent should be in the top left.

I'm itching to try this again but I think it has rained ever since, both day and night. 

[m.tweedy]

any idea on the spacer sizes or pictures for an idiot like me

[JamesF]

Depends what sort of lens you're planning to use.  Different manufacturers have different spacing requirements between the lens and the sensor.  Once you know that you can work out what you need by subtracting the distances for the different components in the optical train.

For example, EF lenses need 44mm between the mounting flange and the sensor.  If the camera sensor is, say, 13mm behind the front of the camera including the T2 thread, then you need 31mm of spacing between the camera and the EF mounting flange on the lens.

I'm not sure what the M42 lenses require.  I did find out once.  45mm?  46mm?

James

[JamesF]

There's a drawing here of the 460EX: http://www.atik-cameras.com/wp-content/uploads/2014/08/series4_mech.pdf

That says there's 13.5mm between the front of the camera and the sensor.  If you wanted to fit a Canon EF lens therefore, you'd need a converter/spacer that would give 30.5mm between the front of the camera and the mounting flange on the lens.

James

[Stardust]

your focus will be at a different point to mine. I have a in built filter wheel and can't remember off hand if I used a 5mm T2 spacer for this lens as I've been fiddling a lot in the obsy trying different things.My adaptor must be around 10mm thick but the lens doesn't focus at the infinity mark, probably half way so you have some room to play with. Are you using a filter wheel with you camera?

[m.tweedy]

Yes the EFW 2.

The reason for my inane questioning is that it's the same lens

Thanks

[JamesF]

Well, it looks like the required backfocus for the lens is 45.5mm (but check that).  The EFW2 takes 22mm of that.  I assume you have some sort of connector to mount the camera on the filter wheel so you'll need to account for the space that takes up between the back face of the filter wheel and the front of the camera.  I can't find a definite figure for that so you'll need to check, but lets assume it takes up 2mm.  Looking at the picture in the manual that doesn't seem unreasonable.  The camera itself takes up 13.5mm.

So assuming my numbers are correct, you should have 45.5 - 22 - 13.5 - 2 = 8mm left between the flange on the lens and the front face of the filter wheel.  I guess ideally you'd want an M54x0.75 male to M42x1 female adaptor 8mm thick (excluding the male thread).

James

[Gina]

I thought Canon EF lenses had a back focus of 54mm and M42x1 (Pentax/Praktica) of 45mm - I'll have to check, it's been a while...