ICEINSPACE
Moon Phase
CURRENT MOON
Waning Gibbous 76.9%
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09-10-2007, 09:19 PM
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Moderator
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Join Date: Aug 2005
Posts: 25,793
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Quote:
Originally Posted by Ingo
Canon Optics are better Takahashi uses Canon's Fluorite Elements
Used 400 F2.8 IS's are very much under the new price, and can be sold for the same price again when you bought it used.
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Quote:
Originally Posted by Benny L
I have the 400 f2.8L IS USM, bought it new for 12K you can pick up ex-press ones for 5-6 K or you can hire from some places for 150-200 bucks a day
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Firstly, I think this thread's wondered off topic because the OP (Andrew) specifically stated a budget of around $1500 not $5-6K and is looking at a relatively widefield lens.
My reply to Ingo was meant more as a subtle hint to this fact than anything else but since the point is brought up - here is my point of view.
There are specific pieces of equipment for specific jobs, in this thread we are solely talking about astro imaging and since we're putting cost to one side let's compare the two glasses and let's say both the Canon 400mm F/2.8 IS and FSQ 106 can be bought for around $6K (AU).
Which would be better suited for astro imaging ???
The FSQ 106 has a 4" Rotatable Focuser, has an imaging circle of 88mm, comes with a 10 to 1 focuser and is an astrograph.
The Canon 400mm IS f/2.8 L is a super sharp wildlife/action/sports lens with one Fluorite element that is designed for these purposes. The fact that it has IS means nothing since IS serves no purpose for astro imaging and since astro imaging places a huge demand on the optics we run the risk of CA showing up due to the IS mechanism not always being perfectly placed in the park position when turned off.
This of course doesn't really show up in terrestrial shots but in astro imaging it has an effect.
Now as you know I'm a big fan of the Canon super primes but if I was to specifically buy glass for astro imaging, my choice would be to get the right tool for the job.
If I wanted to use it for daytime shots as well then I'd consider the Canon lens only because I can use it for other purposes.
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09-10-2007, 09:33 PM
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Moderator
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Join Date: Aug 2005
Posts: 25,793
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Quote:
Originally Posted by andrew
I'm definitely looking at wide-field. As for budget.....less than $1500 is preferable.. The main incentive is to take a step up from the standard lens kit that came with the camera, as it doesn't seem appropriate for astrophotography.
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Andrew I'd seriously be considering any of the following lenses depending on your FOV preference.
These prices are aprox only.
Canon 135mm f/2 L ($1599)
Canon 200mm f/2.8 L ($995)
Canon 17-40mm L f/4 ($955)
Canon 10-22mm EF-S ($899)
Sigma 17-70mm f/2.8 ($515)
Canon 50mm f/1.4 ($459)
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10-10-2007, 02:19 PM
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Bring on the night!
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Join Date: Jan 2007
Location: Dingley Village
Posts: 162
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There are also the cheaper plastic case lens types. The Canon 50mm f/1.8 is only $150 at teds camera house. How would the images from this lens compare with the Canon 50mm f/1.4 ($459) ??? Im only planning the occassional night shot with my Canon400D
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10-10-2007, 03:18 PM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,943
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Quote:
Originally Posted by Domol
There are also the cheaper plastic case lens types. The Canon 50mm f/1.8 is only $150 at teds camera house. How would the images from this lens compare with the Canon 50mm f/1.4 ($459) ??? Im only planning the occassional night shot with my Canon400D
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I have one 135mm Hanimex lens (plastic case) and I found it awful (completely out of centre).
In the course of my testing I found that Pentacon 50mm f1.8 lens (Praktica, ~$50 on ebay) produces quite decent star images, provided it is stopped down to f4 - f5.6. The same applies to majority of Zenit lenses as well.
Generally, prime lenses perform better than zoom's... Of course, if they are in the same price category.
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10-10-2007, 06:02 PM
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Retired, damn no pension
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Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
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The 50mm f/1.8 does a pretty respectable job stopped down to around f/3 or slowere. For a very inexpensive lens it does a good job. It's not an L, but then you aren't paying for it either.
LMC
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10-10-2007, 09:47 PM
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Bring on the night!
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Join Date: Jan 2007
Location: Dingley Village
Posts: 162
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paul,
you siad that you need to "stopped down to around f/3", so what happens if you use the full 1.8 apature? Fuzzy?
Also what's an "L"............that's right i'm a newbie!
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10-10-2007, 10:30 PM
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Registered User
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Join Date: Dec 2005
Location: Carmel - Perth Hills
Posts: 303
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Quote:
Originally Posted by Domol
paul,
you siad that you need to "stopped down to around f/3", so what happens if you use the full 1.8 apature? Fuzzy?
Also what's an "L"............that's right i'm a newbie!
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Using a lens "wide open" will make the imperfections/errors of the glass in the lens more obvious... for me and my work i always stay between 1 stop from fully open and 1 stop from fully stopped down.
so for a 50mm f1.4 i would shoot between f2 and f11, as a general rule the "mid-point" of a lens i.e f5.6-f11 gives the lenses sharpest result. this is because the lens is using the centre most bits of glass in the lens which does not have as much curvature as the outer parts of a lens would. aspheric lenses elements offset this.
if you close a lens all the way down the lens will suffer from diffraction, which is where the image is still sharp but light bounces off of the aperture blades, affecting image quality.
finally an "L" lens is Canon's pro line of lenses but unfortunately they come with a pro price as well. they feature things like weather proofing, more coatings, and various high cost elements like ED and aspherical elements.
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11-10-2007, 10:01 PM
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Registered User
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Join Date: Sep 2006
Location: Melbourne
Posts: 95
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Having done a bit of research I think at the moment I'm leaning towards the Canon EF 50mm f/1.4 lens. I have to say the price is very appealing to me.
One thing though, a problem I have at the moment is being able to accurately focus on the stars with what I use. Will I have any such difficulties if I purchase this lens? I wouldn't expect so given what I've been reading, I guess I just need some reassurance
Thanks for all the info guys, I really appreciate it
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11-10-2007, 11:05 PM
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Registered User
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Join Date: Aug 2005
Location: Hahndorf, South Australia
Posts: 4,262
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Quote:
Originally Posted by Domol
paul,
you siad that you need to "stopped down to around f/3", so what happens if you use the full 1.8 apature? Fuzzy?
Also what's an "L"............that's right i'm a newbie!
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Hello,
Check Bill Christie's pics with the 50mm f1.8... very nice!!
http://www.zodiaclight.com/galleria/wideField.htm
Cheers
Doug
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12-10-2007, 06:24 AM
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Sir Post a Lot!
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Join Date: Sep 2004
Location: Gosford, NSW, Australia
Posts: 36,761
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Quote:
Originally Posted by andrew
One thing though, a problem I have at the moment is being able to accurately focus on the stars with what I use. Will I have any such difficulties if I purchase this lens? I wouldn't expect so given what I've been reading, I guess I just need some reassurance
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Focusing will still be an issue. It's always an issue and always difficult to get right. It's always something you should spend a lot of time on at the start of your imaging session. Nothing worse than taking a whole run and when you get them back on the computer, realise your focus was slightly off and you have blobby soft stars everywhere.
Take some test exposures (ISO1600 for 10-15 seconds) and zoom in on the LCD to check the tightness of the stars. Go back and forth through the focus repeating the test until you get the smallest tightest stars.
You can also hook your DSLR up to a laptop and use software like DSLRFocus, ImagesPlus and others to do effectively the same thing, but it's using maths to determine the quality of the focus and you just look at the numbers as you go back and forth through focus until you find the lowest number (tightest focus).
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12-10-2007, 07:46 AM
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Retired, damn no pension
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Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
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For the 400D look for a freeware program called "Focus Assist". It makes life much easier. I also found that using an on screen magnifier (not the Accessories>Accessibility>Magnifier ) so I can see the pixels makes it much more accurate as well.
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12-10-2007, 08:35 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,943
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Quote:
Originally Posted by [1ponders]
For the 400D look for a freeware program called "Focus Assist". It makes life much easier. I also found that using an on screen magnifier (not the Accessories>Accessibility>Magnifier ) so I can see the pixels makes it much more accurate as well.
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Hi Paul, could you give us a link? I tried to google it but found nothing (except general articles about focus)
BTW, this website has a huge software link library (but not yhis one..) http://astrotips.com/
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12-10-2007, 09:19 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,943
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Quote:
Originally Posted by dugnsuz
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This looks very acceptable, but.. image was taken with lens stopped down to f6.3, so it is not easy to judge... On first occasion (when Melbourne weather permits) I will try my Pentacon 50mm with f6.3 to compare the quality of star images.
What I would really like to see here (or anywhere else) is the simple study of various lenses. cheap and more expensive, with images of reach starfields with some bright stars in the centre and at corners (this milky way is a good test target) taken at the same f settings, so that people can compare apples with apples and pears with pears.
The very good example (but not for what we are talking about here) is this website suggested by mymoon: http://www.samirkharusi.net/televue_canon.html
Unfortunately, most of the time the test reports on lenses (especially if done by non astro-photographers) are very vague, using colourful (poetic even) language with not much real hard data in them.
Also some people belong to Canon club, some to Nikon.. or whatever. Sometimes a lot of money is paid for the specific gear and then it is not easy to admit that almost the same if not better results could have been achieved with significantly lesser investment... the objectivity could be lost very easily if we do not standardize the test method.
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12-10-2007, 09:49 AM
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~Dust bunny breeder~
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Join Date: Nov 2004
Location: The town of campbells
Posts: 12,359
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focusing problems... take the lens off auto focus for one if yu havent done so already and swing it around manually to infinity...
unlike canon, with nikon if it fits the camera you can get focus confirmation, even with an adapted lens... but his doesnt help you.
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12-10-2007, 10:09 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,943
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Quote:
Originally Posted by ving
focusing problems... take the lens off auto focus for one if yu havent done so already and swing it around manually to infinity...
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That will not help either... Mechanical infinity on lens is more than optical infinity...
Also, focus confirmation is not helpful really.
The result depends on how accurate the camera is adjusted (secondary mirror position).
The only way to focus is what Iceman wrote in his reply.. trial and error. But only first time...
If you mark the infinity position on the lens (by lightly scratching it so that you can put it in the same position again), the next time you do not have to repeat the whole procedure.
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12-10-2007, 10:15 AM
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Retired, damn no pension
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Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
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FocusAssist
Only works on 400D and possibly 30D
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12-10-2007, 10:31 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,943
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Quote:
Originally Posted by [1ponders]
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Paul,
thanks for the link.
That's exactly what I need
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12-10-2007, 12:12 PM
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Retired, damn no pension
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Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
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You're welcome. Just remember to name your first DSO discovery after me.
Hmmm... ....[Bok Ponders] has a certain appeal to it
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12-10-2007, 01:28 PM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,943
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Quote:
Originally Posted by [1ponders]
You're welcome. Just remember to name your first DSO discovery after me.
Hmmm... ....[Bok Ponders] has a certain appeal to it
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No worries
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