First Light of the 135mm lens with 2 hours of data

[RB]

This was first light for the Canon 135mm lens.
I decided to do 2 hours worth of exposures on the Rho Ophiuchus Nebula Complex.

It was very cold last Friday night and quite dewy.
I ended up taking 16 x 8 min lights, 16 darks and I applied 15 flats with the Canon 20Da set at ISO 400 and lens at f/2.5.

Final processing was done in PS CS3.

I'm extremely happy with this wonderful lens and look forward to more images from it.

Here's the original image:
Rho Ophiuchus Nebula Complex (Warning 1.1Mb). (http://www.astro-image.org/page/ds/rho.htm)

EDIT: Here's the reprocessed version (1.1MB) (http://www.astro-image.org/page/ds/rho_2.htm)

Hope you like it and as always your comments and suggestions are most welcome.

:)

[Bloodbean]

Wow what a great shot, I absolutely love the colours! What did you use for guiding? What mount was it on? Is the 135mm sharpest at f/2.5?

[renormalised]

Very nice...great colour and lots of detail. Good work!!.

[Zuts]

Hi Andrew,

A really stunning image. the orange, blue and dark nebulas all came up a treat.

It's just my opinion but I think it would look even better with a darkened background, but I guess that is impossible with the number of stars you captured.

Also, thanks for the centering co-ordinates, i couldnt find them last time and want to give this one a go. How much of this do you think i would fit in at 480 ml, or for an object like this would that still be too narrow?

Paul

[Ian Robinson]

I've heard of dark frames , what are flat frames ?

How do you do dark frames on DSLR ? flat frames on a DSLR ?

BTW : excellent photo.

[Garyh]

You lucky bugger! That will be a fine lense for widefield work!
Nice Rio shot!
I agree with Paul about darking the background and giving the fainter dust lanes/areas a bit more contrast without upsetting the central part of the complex. Maybe some midtone stretching?
cheers Gary

[seeker372011]

:thumbsup::thumbsup::thumbsup:

[dugnsuz]

Beautiful image Andrew. The colours are fantastic, and to flog the dead nag - background might be a tad darker. Don't lose that wonderful nebulous detail though!

Like Bloodbean, I wondered about stopping it down to obtain max sharpness. The attached MTF for this lens shows that the sharpest centre and border performance is around f4 - f5.6

When my 40D comes back from its modding, I hope to have a go at this region. And with my 70-200mm L, I'm forced to use f4 (or f5.6 with the extender)!

Nice one. That 135mm lens is a cracker.

[leon]

Great stuff Andrew, gee the are some stars in that image, I hope to have a go at this object, if ever the clouds part, well done indeed

Leon

[RB]

Thanks for your comments guys, much appreciated.

After reading your comments on darkening the background I've had another look at the image on my daughter's LCD this time and it does look bright.
No wonder, I was using my CRT to process it and it looked great on that.
I'll see if I can redo it a little better.


Cheers Bloodbean,
Guiding was done using PHD and the DMK camera.
I managed to sort out the problems which I was encountering during other sessions, turned out to be a faulty USB cord.
The mount I used was the EM400.
The 135mm is at it's 'sharpest' at around f4 from what I had read but I was trying to minimise noise so I had opted for ISO400 and hence used f/2.5 initially to see how this lens performed.
I'll try it at f/4.0 next time and compare.


Thank you glad you liked it.


Cheers Paul, and you're right, it is quite hard to process the background because there's so many stars to deal with.
A F.L of 480mm is too narrow for this region, you would just get a nicely framed Antares in the fov of the 40D @ 480mm ( I assume you want to use your TV85 + FR ?).


Thanks Ian.
You can take dark frames on a DSLR by exposing for the same amount of time but with the lens cap on.
Flat frames record any irregularities in the optical train and are subtracted from the light frames so that they flatten the field and remove and dust spots/vignetting etc.
I take flat frames in the morning by pointing to a clear even patch of blue sky and exposing in P mode so the histogram goes 1/3rd the up.


Thank you Gary, yes it's a great lens, can't wait to try it out on some terrestrial shots.
I'll have another look at the background when I get a chance.


Cheers Narayan, hope we get some more great weather again soon.
:thumbsup:

Glad you liked it Doug and as I said earlier I wasn't sure how I'd go with the 20Da for 8min so I used ISO400 and opened the lens up.
Definitely next time I'll go around f/4.

You're 70-200mm will give you a great choice in framing this area perfectly.
Can't wait mate.

:thumbsup:


Thank you Leon, hope we get good weather again soon.

[jase]

Great first light image for the 135mm lens RB. I agree with Paul, your background is too set too high. As a result your colours appear muted and dusty lanes washed out. Perhaps try raising the black point by 36-40 points and subtly boost saturation to get a little more colour if desired. Overall well done.

[RB]

Thanks everyone your input is much appriciated.
I was trying to bring out the detail but indeed the final image did work out too washed out like Jase and others had said.

Jase I tried to apply some adjustments you suggested, thanks for that.

It was tricky to redo the background and still retain a decent looking histogram, had to use some layering too.
Do you think that maybe the 8 min subs with the lens almost wide-open may have saturated the frames and reached sky glow limit? :shrug:

Anyway here is the link to the new version which is an improvement I think.
See what you think guys?

New Version (1.1MB) (http://www.astro-image.org/page/ds/rho_2.htm)

Original Version (1.1MB) (http://www.astro-image.org/page/ds/rho.htm)

[dugnsuz]

New one is nicer Andrew I reckon - really pulls out the colours more.
Well done
Doug

[jase]

The reprocess has nailed it RB. Looks much better. You'll need to test your sky fog limit. 8min @ F/2.5 maybe pushing it. Could be ok for dark skies. Perhaps stop down the lens one more time. Well done on the reprocessed ver.

[iceman]

Hey RB I love the repro, I though the same when I saw the original.

Processing on different monitors is a real PITA.

Awesome view of this lovely object.

[astro_south]

Great image Andrew ... would look that little bit better if it was flipped along the vertical axis to match our view of this area in the sky ;) :thumbsup:

[h0ughy]

WOW that is a real keeper Andrew. well done

[marc4darkskies]

Nice treatment of a beautiful subject Andrew! :thumbsup: The reprocess did the trick! I agree with the others though, next time, stop the lens down a bit (probably by 2 stops) to sharpen things up a little.

Cheers, Marcus

[RB]

:thumbsup: Doug


Thanks again Jase, yeah I think 8min,f2.5 for this lens is pushing it under my skies here, I'll have to stop it down because the data was very difficult to process.


Cheers Mike, I couldn't believe how different it looked on the LCD.
It really is a pain processing for different types of monitors.


LOL nice spotting there Andrew, I was wondering if anyone was going to pick that up. ;)


Thanks David, I love this area of sky.


Glad you liked it Marcus, I certainly will stop the lens down more, just wasn't sure on first light how it would go, usually I go above f/2.8 on the others.

[acropolite]

Nice Job RB, a very pretty area of the sky. Good to see you managed some time to yourself. You imaged this area before with an 85mm in this thread (http://www.iceinspace.com.au/forum/showthread.php?t=31656). I still remember the beautiful colour.:thumbsup:

[Garyh]

Ah...missed the reprocessed version.....
Much, much better Andrew.
Colors are much better and more fainter dust clouds are now showing from the background.
Excellent..
At home under semi-dark skies @ f/2.8 I can go to around 6min at 400 iso before skyfog starts giving the image that greenish look..
If you stop it down to f/3.2 or slower it might help but I don`t know how dark the skies are your way?
cheers and have fun!
cheers Gary

[RB]

Thanks Phil, yes it's nice to get some time to actually image.
Usually too busy or the weather's not behaving.


Cheers Gary, it made a huge difference in the end and I'm quite happy with it.

My skies here are deteriorating due to urban/industrial sprawl and I notice a big change within the last few years.
These lenses are super fast and I need to take it all into account when estimating the exposures. As I said it was difficult to process this one.
Learning all the time.

:thumbsup:

[Tamtarn]

Impressive first light with the 135 Andrew. Lovely composition. Certainly like the reprocessed version.

[RB]

Thanks guys, it's a great patch of sky to image and a fun lens to use with this particular FOV.

:thumbsup: