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Old 17-06-2010, 09:00 AM
bloodhound31
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Widest and fastest lens without curvature

I posted this on a photography forum, but Troy suggested I ask the knowledgeable folks here and I reckon you guys would have a better understanding of the photographic intent at night. I thought I might elaborate a bit more to give the full picture and therefore get better answers.

I am looking for the best lens for the 5DMKII (I'm getting this very soon) to get in as much night sky as possible (Milky Way shots) without having the field curvature/distortion.

The other night I was out with a beautiful view of the milky way from horizon to horizon, a nice treeline, a rocky hill in the background and a lone pine tree in the foreground. I wanted to get a lot of that in, but all I could get was the top of the stinkin' tree and a small section of the centre of the milky way bulge.

I HATE the fisheye effect and need a lens that is fast, wide and straight all the way to the edges. A little bit of vignetting at 16mm on a full-frame sensor is normal I understand and forgivable, as the long exposures will be pretty dark anyway.

Any suggestions? 16-35? 10-22? Canon L series? Sigma? Other?

Any slower than F/3.5 is not an option. Currently using a 400D with a kit 18-55 F/3.5 lens and had a gutful of it. Got to move on to the 5D and another lens for this, PRONTO!

CAVEAT: I still need just a little flexibility to zoom for normal daytime stuff, so I am thinking the 16-35 is my best option so far... I do need to be able to shoot in a room without having to knock out a wall to get it all in. I'm not getting rid of my existing gear so I will still have the 400D and kit lenses to do the in-between daytime stuff.

Baz.
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Old 17-06-2010, 09:48 AM
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sejanus (Gavin)
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I haven't pointed it at the sky, but generally speaking the Zeiss 21mm 2.8 makes the canon 16-35 look like a coke bottle.

http://www.adorama.com/ZI2128DTZE.html

If you do need flexibility then the 16-35 is the ticket, however compared to the zeiss it needs to be stopped down significantly to be performing very well. The zeiss 21 is so sharp that in my wedding photography I've actually had to soften files with it for album printing.
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Old 17-06-2010, 09:53 AM
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Interesting Gavin. Thanks mate, I've never seen that one before.
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Old 17-06-2010, 09:55 AM
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it and the 35/1.4 are my "planned" lenses to do widefield with once I get a eq mount.
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Old 17-06-2010, 09:58 AM
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btw the zeiss is manual focus only
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Old 17-06-2010, 11:16 AM
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G'day Baz. Still don't understand the f/3.5 requirement. Can you explain a little more about why that's an issue?
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Old 17-06-2010, 11:19 AM
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G'day Troy. I really appreciated your input on the other post mate. Thank you.

I want a faster lens so I can cut down my exposure time, therefore cleaning up star trailing and also noise. When I am doing time-lapse, I am coming home with 800 to 1200 frames. With shorter exposures I will have more again. I really don't want to be messing around too much subtracting darks from this many frames.
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Old 17-06-2010, 11:32 AM
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The prob with that is mate that most zoom lenses need to be stopped down to be sharp. Most zoom lenses are pretty average wide open - the 16-35 is a big example of that. Though it can shoot at 2.8 it's pretty soft there, and vignettes a bit as well. It really only starts to shine at 5.6 or smaller - though this depends how picky you are. As you stop it down further and further (until f8'ish) it picks up colour/contrast/sharpness & the vignette goes away (mostly).

For terrestial photos, I try not to use the 16-35 wider than say 4.5'ish.

And this is why I mostly use primes.
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Old 17-06-2010, 11:38 AM
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Thanks Gavin.

If that's the case, then I may need to get both the 16-35 for some specific shooting I have in mind, and a wide, fast, flat prime. Any recommendation there? Again, I already have 18mm capability on a cropped frame. I am moving to the full frame and want LOTS more sky for my Milky Way time-lapses.

Edit: When you are including foreground in a starry time-lapse, IMHO, nothing looks worse than the fisheye look or bent horizons.
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Old 17-06-2010, 11:46 AM
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Have a look at www.rugift.com.
They have interesting lenses, at reasonable prices..
Manual mostly, though.
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Old 17-06-2010, 11:47 AM
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Aah, reason I was asking has already been covered by Gavin. Even though the lens is faster, you'd be best to stop it down a bit for sharpness.

As I said on POTN, why not just up the ISO? What ISO have you been using?
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Old 17-06-2010, 11:47 AM
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yeah I'm not a fan of fisheye shots of the sky either

with no consideration of money it'd be ;

- canon 14/2.8 II
- zeiss 21/2.8
- canon 24/1.4 II
- canon 35/1.4

decide how wide you want they all kick butt. I've used them all - my fave is the zeiss. 14 is a bit wide for me though optically it rocks.

there are much (much!) cheaper ones like 20/2.8, 24/2.8, 28/1.8, 28/2.8, 35/2 but I've never used them personally so you'd need to google a bit for reviews and samples I guess.
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Old 17-06-2010, 12:02 PM
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Quote:
Originally Posted by troypiggo View Post
Aah, reason I was asking has already been covered by Gavin. Even though the lens is faster, you'd be best to stop it down a bit for sharpness.

As I said on POTN, why not just up the ISO? What ISO have you been using?
From what I understand, upping the ISO doesn't bring any more light into your chip, it just turns up the volume of the photons gathered, like turning up the sound volume on your stereo. It also turns up the volume of all the false light (noise).

In my limited experience, every time I have upped the ISO, especially for this sort of shooting, the noise gets lots worse, coupled with horrible horizontal lines right across the frame. I wish I could shoot at ISO400, but I am usually on ISO800 and the noise is yuck. If I got a F/2.8, perhaps I could still expose for 30 seconds, but drop the ISO. That would probably be sweet.

Besides messing around with dark subtraction from a couple of thousand frames, I see no way past that except to bring in more light in the first place and shorten the exposure. One really wants to be doing as little PP as is necessary.
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Old 17-06-2010, 12:12 PM
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Quote:
Originally Posted by bloodhound31 View Post
From what I understand, upping the ISO doesn't bring any more light into your chip, it just turns up the volume of the photons gathered, like turning up the sound volume on your stereo. It also turns up the volume of all the false light (noise).

well...the rules of photography still apply. though in the background yeah the sensor is turning the gain up - you still end up with more light in the end file.

remember the 5d mk2 will be ridicoulously better in low light than your current gear, 1600/3200 iso is not a problem at all.
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Old 17-06-2010, 12:13 PM
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Yeah, gotchya. Higher ISO will increase noise. You haven't said what ISO you're using, but you'd expect the noise levels to be much lower if you're going to a 5DII instead of your 400D at the same ISO. Would have thought ISO1600 would be acceptable on a 5DII. Maybe ISO400 to 800 on the 400D?
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Old 17-06-2010, 12:15 PM
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Gavin keeps replying while I'm typing and beating me to the punch
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  #17  
Old 17-06-2010, 12:20 PM
bloodhound31
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Quote:
Originally Posted by sejanus View Post
remember the 5d mk2 will be ridicoulously better in low light than your current gear, 1600/3200 iso is not a problem at all.
That's the prayer mate!

Quote:
Originally Posted by troypiggo View Post
Gavin keeps replying while I'm typing and beating me to the punch
Sorry Troy, I edited in the ISO I am using.
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  #18  
Old 17-06-2010, 12:36 PM
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Once upon a time, I had the 28mm f/2.8. It was a lovely lens. Would probably have been better on the fulll frame. Never had the chance to try it out.

I've done 10-minute exposures with the 5D Mark II at ISO-1600 pointed at Eta Carinae, and, it was clean, clean, clean.

I see no problem with doing short exposures at ISO-3200 -- look at Phil Hart's work or Alex's using his D700.

H
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  #19  
Old 17-06-2010, 12:41 PM
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Sorry Troy I'm a bit clueless with scopes/mounts etc. but when it comes to camera lenses it's my world
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  #20  
Old 17-06-2010, 08:52 PM
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Baz,

You could always toss the Canon and get an Olympus 7-14mm - its near perfectly rectilinear (and so essentially without distortion) and remains so wide open.
Ahhh but its f4 (close to f3.5 by a bees whisker - remember its not a linear scale)
Also the "crop factor" is 2X due to the sensor - so thats more like 14mm focal length in 35mm terms

Or stick with the sensible advice !!

Rally
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