zeiss mc-s 135 3.5

[alacant]

Hi

Does anyone have any astro samples taken with this lens?

Cheers

[Daf1983]

I bought this lens a few weeks ago. This is what I've managed with it so far. Don't be put off with these images though, as I'm a complete novice, and my processing skills aren't the best

[Moonshed]

“I bought this lens a few weeks ago. This is what I've managed with it so far. Don't be put off with these images though, as I'm a complete novice, and my processing skills aren't the best.”

Hi Daf1983, there’s nothing wrong with your processing skills!

[Daf1983]

40 minutes ago, Moonshed said:

“I bought this lens a few weeks ago. This is what I've managed with it so far. Don't be put off with these images though, as I'm a complete novice, and my processing skills aren't the best.”

Hi Daf1983, there’s nothing wrong with your processing skills!

Thanks for your kind words. I would have been overjoyed with those images when starting a few months back, but I suppose you become more self critical as you gain some experience. 

[alacant]

Thanks for the references.

We tried an example over the weekend.

II's nice. It doesn't give the usual undersampled looks-like-it's-been-taken-with-a-cheap-lens type images; better than my Takumar 135. Focus is however super critical as outlined below.

Apart from being painfully slow at getting the light captured, one annoying point is that the diaphragm blades have a sharp notch-indentation at each corner which produce spikes even on dim stars. Gonna try some step down filter rings instead. Focus against the lens stop gives red star halos with true infinity being around 1/10 of a turn away. The best way we found was to centre say, Capella and focus away from the lens stop until the red halo just disappeared. Focusing with a Bahtinov yields red halos, so not much use with this -and many other- old lenses.

 

Here are some samples two clicks down from open. Not sure what that would be as there seem to be several click stops between those marked on the lens barrel.

Thanks again and HTH.

** Do we think a thread, imaging with vintage lenses, would be useful?

 

Edited December 13, 2020 by alacant

[Daf1983]

This is very interesting and informative. I also noticed the notches on the diaphragm, wasn't sure if that was normal for vintage lenses, as this is the only one I've used. I also get red halos around bright stars when focusing, and like you, focus by making sure these disappear. 

I would definitely be interested in a vintage lens thread, as that's all I can afford for the time being

[AnonymousAnimosity]

12 hours ago, alacant said:

II's nice. It doesn't give the usual undersampled looks-like-it's-been-taken-with-a-cheap-lens type images; better than my Takumar 135. Focus is however super critical as outlined below.

Apart from being painfully slow at getting the light captured, one annoying point is that the diaphragm blades have a sharp notch-indentation at each corner which produce spikes even on dim stars. Gonna try some step down filter rings instead. Focus against the lens stop gives red star halos with true infinity being around 1/10 of a turn away. The best way we found was to centre say, Capella and focus away from the lens stop until the red halo just disappeared. Focusing with a Bahtinov yields red halos, so not much use with this -and many other- old lenses.

 

 

I have been using this lens for a couple of months and I've never managed to focus properly with liveview, maybe it would be easier with the camera connected to a PC. Yesterday I tried making a quick Y mask and realized that as you pointed out when the spike is centered the red channel is actually way out of focus leading to red halos around the stars. Maybe it would be helpful to still use the mask balancing the spike's position in the 3 separate channels?

This is a comparison of the 3 channels of a quick picture from last night taken with a modified canon 100D and a clip in l-enhance filter. I set the aperture ring to around f/5.6 but I did not notice the camera was on A mode, so the lens was wide open.

[rickwayne]

So, really great for narrowband, is what you're saying!

Gotta say, alacant, those look reeeally nice. I don't even mind the spikes so much, though I agree a circular mask would be a great addition.

[alacant]

9 hours ago, AnonymousAnimosity said:

camera connected to a PC

Yep. Essential. The camera screen is hopeless. We used EKOS' live view at 10x.

9 hours ago, AnonymousAnimosity said:

aperture ring to around f/5.6 but I did not notice the camera was on A mode, so the lens was wide open.

Perhaps you mean the lens was set on A? 

Cheers

 

[alacant]

1 hour ago, rickwayne said:

great for narrowband

I'm surprised to see so much blue.

@AnonymousAnimosity I wonder if we have the same lens? On our example, the blue and green coincide almost perfectly. Maybe it's the filter... Dunno.

Cheers

[AnonymousAnimosity]

On 14/12/2020 at 21:21, alacant said:

Perhaps you mean the lens was set on A? 

That is what I meant yes.

On 14/12/2020 at 23:02, alacant said:

@AnonymousAnimosity I wonder if we have the same lens? On our example, the blue and green coincide almost perfectly. Maybe it's the filter... Dunno.

I do believe we have the same lens judging by your picture. In the previous post the images of the three channels were in the wrong order, the out of focus one is red, so green and blue are very close.

The filter definitely alters the focus across the 3 channels a bit, these are excerpts  (R, G, B.) from a picture that was taken without.

Edited December 16, 2020 by AnonymousAnimosity