5D Mark III, single exposure

[Octane]

All,

I headed out bush tonight hoping for dark skies. They were dark, indeed. However, I was thwarted after my first exposure; I had hoped to capture at least an hour's worth of data, but, the fog had other ideas.

This is a 6 minute single exposure.

Canon EOS-5D Mark III, Canon EF 50mm f/1.8 II, Vixen Polarie
360s f/5.0 at 50.0mm iso1600

Larger version here (http://users.tpg.com.au/hqureshi2/tpcecn.html).

Can't wait to play more with this combination. :)

H

[koputai]

Very encouraging H, were any filters used?

Cheers,
Jason.

[Irish stargazer]

Very nice. Very low noise for a 360s exposure.
I am hoping to try my new Polarie and Canon 7D at the ISSAC event next week to see what it can do. I doubt I will get anywhere near that length of exposure with the cameras inherent noise levels. Will try though ;)

[gregbradley]

That is VERY nice. Good choice with the exposure settings.

Shame the fog interrupted your imaging session. No amp glow and nice and clean. You nailed polar alignment too.

Greg.

[multiweb]

Awesome shot. 6min at 50mm. Pretty cool. :thumbsup:

[dvj]

Holly smokes! That' just perfect

[alpal]

Beautiful shot.
That 50mm lens is a winner.

[Larryp]

Great shot, H!

[danielsun]

Great result for 6 min. H :thumbsup:
I am also loving the convenience, portability and performance of this great little Polarie unit. I also love the 1/2 speed function to include some landscape.:thumbsup:

[Gruffalo]

That is a nice image.

[batema]

It is a great little lens isn't it. It looks fantastic and it is a single shot. Can't wait to see lots of exposures.

[MrB]

Very nice H! You have the PA nailed with that Polarie. Shame about the fog killing your night :(

Could I tempt you to get that cam modified?! hahaha no just kidding.
Same region with 60Da, 50mm Pentax lens, 300sec, 1600 iso:
http://www.iceinspace.com.au/forum/attachment_browse.php?a=117851

[trek1701]

Amazingly sharp for this lens at f1.8:)


Cheers Mark

[pluto]

I thought the same thing when I first saw it but it's at f5. It's an awesome little lens but sharp wide open it aint ;)

[astroboy]

Looks promising H , have you done a comparison with the mark II at a larger scale ? hard to tell what the noise is really like in the MKIII
One think that does look good is the Ha response do you think its any better than the II.

Z

[astroboy]

Sorry I was looking at Simon"s 60Da pics when I thought the Ha was so good:rolleyes: Still a nice shot though .

[allan gould]

Great image H and your equipment is really producing great photos.

[trek1701]

Thanks for the correction Hugh

[leon]

Top effort H for that combination, that fog is always a kill joy, seems like you have it mastered though.

Leon

[Peter Ward]

Very cool :thumbsup: :thumbsup:

[UniPol]

Great shot

[Octane]

Jason,

Cheers -- I was quite pleased. :)

No filters. Just straight camera and lens. :)



John,

Thanks!

If you have the polar scope, there's no reason why you can't also achieve the same exposure length. I've managed (so far) up to 8 minutes at 40mm. :)



Greg,

I thought you might be interested to see this one. :D

Yes, I spent a considerable amount of time with the polar scope getting precise alignment. The hardest part is finding Beta Hydri, but, I've got that down pat now, too. :)



Marc,

Cheers. :)



John,

Wow, high praise, indeed! Thank you, very much. :D



H

[Octane]

alpal,

Cheers! That lens is the cheapest l own. It has always been used as a dust cap on my 1-series. Thought I'd have a bit of a play with it as it is lightweight, and well-suited to the Polarie.



Laurie,

Thank you, sir. :)



Daniel,

I never realised just how useful this little device is. Best grand I've spent so far (I got the whole kit with inclinometer, polar scope, tripod and extra ball head). I haven't tried the half-speed function, and, I probably won't. I'll just take a static image for the landscape first and then follow it up with the stars. Blend the two in post, et voila!



Gruffalo,

Thank you! And, welcome to the forum. :welcome:



Mark,

Absolutely! I'll try and get out again this week if I can. I've just finished 12 hours of wedding work, so, am buggered, otherwise I would be out tonight. :)



H

[Octane]

Simon,

Thanks, dude! Yeah, I was pretty peeved with the fog!

The polar alignment was so dead on, that, the next exposure that I took (which was ruined by fog) still had the very same stars at the edge of the frame. Not one missing!

Your image looks spectacular, too. I had pretty much the same colours (except the extent of hydrogen alpha) in my own. I changed the white balance to darken the sky and added contrast.

Looks like you nailed your polar alignment, too!



Mark,

lol, this lens is trash at f/1.8. It is so horrible at the edges. I gauge my exposure settings by opening up and shooting at ISO-3200 until I get what I like. I then work backwards and choose the appropriate exposure for the aperture/ISO combination I want. I knew that by closing this lens down by 3 stops, that I'd get a lot better results. And, I could see it in the test exposures. f/1.8 was horrible, f/3.2 was better, but, by f/5, the edge was fairly pin point.



Zane,

Thanks for checking it out!

I haven't done a comparison with the Mark II. I should try that at some stage. As Phil Hart and others have already done the exposure examination work, they will tell you that this camera doesn't have more than 1/3rd to 2/3rds of a stop better noise control.

For weddings, I can confidently shoot at ISO-3200 and know that I'm going to get a cleaner image over the Mark II.





Allan,

Thank you, kindly! I blame the equipment, each time. :D



H

[Octane]

Leon,

Thanks! You should get one! :)



Peter,

Thank you. :D



Steve,

Appreciate it. :)



Thank you, one and all. I wasn't expecting this type of response. :D

H

[DavidU]

Kewl as:thumbsup::thumbsup:

[Octane]

Thanks, David. :)

Haven't heard from you in a while -- hope all is well.

We'll have to have a Doug's chatroom reunion!

H

[Merlin66]

Very nice!
Running at f5 you only have 10mm aperture...and still get results like this!
I have the "nifty 50" and the 85mm f1.8 prime to try out with the fully modded 1000D for objective spectroscopy.....maybe toooo many star images in the FOV!

[astronobob]

Nice result from a single image H & interesting your findings with the F/Stops etc with this lens, as I picked up a 50 myself recently.
Dig the Subtle processing, looks reallistic to the eye, Top shootin ,,

[avandonk]

Humayun I took the liberty of using your fine image as a test. I split a tif generated from your image into separate RGB fits.

I just used the contrast module in StarTools on each fit. Put the image back together.

The gradients are GONE!

Here is an animated gif 2MB

http://d1355990.i49.quadrahosting.com.au/2013_05/humayun.gif

Below is a before and after.


Sorry to shout, but this is a really good method for eradicating gradients without affecting the underlying data. This should be useful for any imaging. My guess is that it would remove or at least reduce fog and haze in terrestial images. It removed the sky glow and or the bit of light pollution? that was there in your image.


Bert

[Octane]

Hi Bert,

I kind of find the image with the gradients removed to be overly contrasty. What do you reckon?

I've mentioned before that I'm a fan of low contrast images, so, maybe it's just a personal preference. When I get the chance, I'll run the image through IRIS and PixInsight and see how they handle the gradients, too, as that's all I have access to at the moment.

Certainly looks promising, though. Ivo's done an outstanding job on his software -- I saw his presentation at the last AAIC and I could tell how much passion and energy went into his baby.

H

[avandonk]

A poor quality jpg is a very bad starting point. That being said the contrast has not been affected to any great degree. I can only surmise that the removal of a layer of polluting light intensity will allow more headroom to increase contrast. It is an optical (brain) illusion that this is severe.

Bert

[Paul Haese]

I'm with you H. The image Bert produced is has far too much contrast in it looks very dark with no subtle dust lanes showing through.

[frenchbluehour]

beautiful image :)

[gregbradley]

I agree too contrasty and looks black clipped. I'd say the gradient is more black clipped than removed. After all its a contrast tool that was used. There are better ways to remove gradients that don't affect overall light levels.

Still it could be a useful tool on some images that are a bit washed out.

Greg.