cheepo m42 lens

[alacant]

Hi everyone. I saw this old lens on ebay for around €30. You need an adapter but they're easy to get.  It turns out nice stuff. Here's one I took along with my effort at getting the corners sharp with the st lens tool. Maybe a better lens would give me a flatter snap as I can't see any way of correcting other than in software. The exposure was a guess so any tips and target recommendations most gratefully received. Cheers and clear skies.

**Oh, and as you can see, I can't do colour balance. Just can't.

 

[happy-kat]

I love old lenses too, to unison fr corner sharpness you could try both of these.

Stop the lens down to f4 or so.

Focus on a star that is where the thirds intersect

That lens looks a bit like my old Helios 135mm though my lens has a built in lens hood, I use a home made flower pot flocked shield on the other lenses.

[alacant]

Hi. Thanks. No chance to focus since infinity is up as far as it will go. I tried f4 and f5.6 but both introduce star spikes. And I can't live with spikes. 5.6 is the limit for me I think. Oh and yes. I found the lens hood. It slid out unexpectedly. Distorting it slightly makes it stay put

 Here's another ebay special -only €20 this one- which will focus, except that with everything so small, it's really difficult. I had APT live view zoomed in on Vega with the magnifier on top and still it's not clear. The boiling atmosphere doesn't help of course and changing focus direction moves the image enough for it to be annoying; I don't think I've hit it here. But what can you expect from a 40 year old lens? TBH I wish I'd taken the advice here and taken this route into photography to begin with. Hanging a camera on the end of a telescope is so much more difficult.

 

[happy-kat]

Defraction spikes caused by the aperature blades, you could make a cardboard circular mask instead to stop the lens down, this will not give star spikes but might improve your corner stars as you will still be stopping the lens down.

Not all adaptorr support infinity focus check that the for sale listing does say the adaptor you are looking at will.

I use my 7 inch tablet screen and dslr controller to help me get focus as I don't have a laptop. I think as long as you can focus on a bright star in the same general direction you will then be pointing the camera it doesn't matter if you focus and then move the camera a bit to point at what you want to image.

What make is your 135mm is it a Helios? I've found mine quite good for Motorsport images at f8, very slight CA but sharpness is good.

[Stub Mandrel]

See if you can get a Carl Zeiss Sonnar 135 f3.5 tele lens.  Brilliant for wide field and sharp even if wide open.

 

 

[happy-kat]

It's a very crude sketch but for focusing ideally use a star that is on one of the third intersections, don't use a star in the centre. This I gather evens out star focus across the frame.

[Alien 13]

I still use M42 lenses for daytime video they are quiet and have nice smooth focus action, you can buy step down adapters for filters these work well as aperture masks.

Alan

[Atreta]

this one looks like a Tokina 135mm i have.  it gets infinity focus with no problem,  but i have to stop it down to   f5. 6 because of chromatic aberration.  never paid attention to the corners so i can't tell right now  if it is sharp in there too.  I'll try to find the images i took with and post here. 

[alacant]

Thanks everyone. I think I have a winner. Sharp everywhere with deneb focused on a third (tks happy-kat) and then recomposed in cdc. No idea you could fit nikon -my non astro gear- on canon. Also it needs less than half the exposure of the zeiss 50mm. @atreta the 135: it's this lens

 

 

[Knight of Clear Skies]

Another fan of M42 lenses here, here's a quick guide I put together on suitable lenses and some tips for using them if you're interested.

[happy-kat]

That's a nice fast 50mm lens you have there.

[alacant]

Hi. 

42 minutes ago, Knight of Clear Skies said:

Another fan of M42 lenses here, here's a quick guide I put together on suitable lenses and some tips for using them if you're interested.

Thanks. I really MUST make an effort on getting rid of that red cast. Your photos are so much better properly balanced...

[Stub Mandrel]

2 hours ago, Knight of Clear Skies said:

Another fan of M42 lenses here, here's a quick guide I put together on suitable lenses and some tips for using them if you're interested.

Very interesting - I am still to realise the true potential of my 135mm Zeiss Sonnar, all I have proven so far is it is pin sharp but I haven't done much with it!

I wasn't ashamed of the pictures I got last year with my 400mm PrinzGalaxy - a budget lens when I got it second hand in the 1980s (like the Zeiss), bearing in mind I was using an ancient unmodded 10D for this: