28 replies to this topic

[stevecoe]

Howdy all;

 

I am looking to upgrade my Sigma 70 to 300 zoom to a Canon 300mm L prime lens for imaging the sky.  I have no doubt it will be much better than the Sigma.  I am planning to buy used from KEH and am wondering if anyone is already shooting with this set up.  I have a Canon T2i body and am very happy with the results so far.  I just need to save up the money.

 

Clear skies to us all;

Steve Coe

[mvas]

I had read some where that some Canon Lens were not as sharp to the edge, as the non-Canon Lenses. Now, I have find that article ...

[dugpatrick]

I like my (older) non-IS Canon 300mm L prime lens.  Wide open is fine for narrowband, but for RGB I normally step down to f/5 to avoid chromatic aberrations on the edges.

 

Example astro pictures:

https://www.flickr.c...N05/24706233426

https://www.flickr.c...N05/11863541115

https://www.flickr.c...N05/16512411821

 

Doug

[stevecoe]

Doug;

 

There are some excellent shots, now I am really looking forward to having the lens.  Lots of excellent detail and sharp stars.  I like the field of view with that 300mm as well.  Thanks for sharing.

 

MVAS, I am considering the older f/5 version of this lens, I don't have the money to buy it new.  I have also heard that older lenses for astroimaging are better.  There are several of them available at KEH in Atlanta.  It will take me some months to get the money together.

 

Clear skies;

Steve Coe

[kbastro]

I use one 300mm L from time to time,,, here is a sample shot using a canon 60da w/300 at f/4.5 and taking a single 60 second shot, should give you the heads up on what this little lens can do!

kbastro

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Edited by kbastro, 21 March 2016 - 09:43 PM.

[calypsob]

I have seen a few images on astrobin that have no Ca wide open with this lens. I tend to think that the Ca is due to improper focus. It is hard to tell. It seems to be common for people to over expose stars white with this lens so that its difficult to discern Abberations. I look forwards to more posts regarding the lens as I am in the market as well. 

[andysea]

I had the 300 f4L i.s. 

I used it wide open and don't recall much CA however I was getting some star elongation even in the center of the frame (using my Mach1).

I think my sample needed to be collimated. I ended up selling it as it was great for daytime photography.

[Ron359]

  I use the 300mm f/4 L lens mainly for wildlife but tried it last year for some images of Comet Lovejoy at f/4.  Attached is a non-cleaned-up example.  This is with an APS-C size sensor on a Canon T3.     

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[Red Brick]

There are a lot of good lenses out there and some at a hefty price. The stock lens 75-300mm that came with my T3 is OK but not spectacular as getting edge to edge focus can be tough sometimes. I too am looking at a 100-300mm fixed lens but am having some difficulty on accepting a large price on a lens with a limited function but astrophotography. I am considering building a lens and I am looking over a couple of designs.

[RenaudVL]

Hi,

Did this with the older 300mm f4 L FD.

I had converted the lens from FD to EF mount using an Ed Mika conversion kit, so the lens can achieve infinity focusing ...

Very happy with it!!!

 

[FiremanDan]

I have been thinking about getting a nice 200 or 300mm L prime. Used of course. But they seem like great for AP and I love how good they seem for daytime work too. I just got to add that to the list of things I need to save up for.

[FiremanDan]

Hi,

Did this with the older 300mm f4 L FD.

I had converted the lens from FD to EF mount using an Ed Mika conversion kit, so the lens can achieve infinity focusing ...

Very happy with it!!!

 

 

 

I have head mixed things about FD lenses and EF/EFS cameras.
What is that mod all about? Is it just one of those adapters?

[RenaudVL]

 

I have head mixed things about FD lenses and EF/EFS cameras.
What is that mod all about? Is it just one of those adapters?

 

 

 

Hi,

This is not like the other adapter, it has no glass component that allow for infinity focusing.

It is actually a complete bayonet replacement kit. It allows for infinity focussing without additional glass component...

It is a do it yourself kit.

 

http://edmika.com/

 

Like I sais, I very satisfied with my converted lens....

[FiremanDan]

 

 

I have head mixed things about FD lenses and EF/EFS cameras.
What is that mod all about? Is it just one of those adapters?

 

 

 

Hi,

This is not like the other adapter, it has no glass component that allow for infinity focusing.

It is actually a complete bayonet replacement kit. It allows for infinity focussing without additional glass component...

It is a do it yourself kit.

 

http://edmika.com/

 

Like I sais, I very satisfied with my converted lens....

 

 

 

Hmm... interesting.

I don't see it said, can you use autofocus with those? Probably not if I had to guess.

[RenaudVL]

No, it is a manual focus lens to start with...

[tjones84]

I've used my Canon EF 300mm F/4L USM for astrophotography plenty of times, and I really enjoy this focal length - both with a crop sensor DSLR and Full Frame.

 

I bought this lens used - it's the old Non-IS version

 

Most recently, I captured the Orion Nebula and surrounding area with the Canon 300mm F/4L riding on a SkyGuider Pro:

 

 

It's a nice portable setup - that I like to use on nights when the forecast shows only 2-3 hours worth of clear skies.

 

I like to use this lens at its widest aperture of F/4 to really take advantage of the optics. The stars are always sharp to the edge. 

 

It's a really great camera lens for astrophotography. At 300mm - it's pretty forgiving as far a tracking error goes - so no autoguiding needed even on 2-minute + exposures.

 

Here is my Orion shot using this setup:

 

 

The image includes 2 Hours and 49 Minutes of total exposure. ISO 400, 90-second subs using a Canon Rebel T3i. 

 

You can read my full post about my experiences with this lens - and see the full size image here: Using a Canon 300mm F/4L Lens for Astrophotography

 

Curious to know if anyone else is using this particular lens for AP?

 

Cheers all!

[VincentD]

 

Curious to know if anyone else is using this particular lens for AP?

 

 

Hi Trevor,

 

I have recently completed my first deep space photo using the Canon 300mm non-IS. Mine has some purple fringing  wide open, so I used step-down rings to close it to f/5.45. 

I could get a better result from an APO refractor, but the lens is smaller and lighter - that's important to me because I live in a very light polluted country and I sometimes take a flight to La Palma or a Greek island to have access to a good dark sky, so weight is an issue.

 

Cheers,

Vincent

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[Messierthanwhat]

I like my (older) non-IS Canon 300mm L prime lens.  Wide open is fine for narrowband, but for RGB I normally step down to f/5 to avoid chromatic aberrations on the edges.

 

Example astro pictures:

https://www.flickr.c...N05/24706233426

https://www.flickr.c...N05/11863541115

https://www.flickr.c...N05/16512411821

 

Doug

I'm using the same older lens, with pretty much the same results. Mine breaks down a bit more in the corners than is evident from Doug's images, but it actually seems to improve a bit with the matched 1.4X TC.

[Woodbridge_Dave]

I would advise against a DSLR lens for DSO Imaging, even the venerable L series.  Using a camera lens for telephoto astronomy is a classic newbie mistake, and I can say from experience I’ve been there (10 years ago).  Reasons to avoid a lens for DSO Imaging :

 

(1) look at M42 above by tjones84.  With respect, the stars are bloated & the image has a fuzzy look.  This is what I would expect from an achromat.

 

(2) the 300mm f/4 L lens puts 15 pieces of glass between your sensor and space.  Every one of those interferes with light transmission.  A simple 70mm ED refractor has 2 pieces of glass. 

 

(3) the cost of a 70 mm ED refractor is half.

 

(4) Camera lenses (even L lenses) do not flatten the field effectively.  They were never designed to shoot pin point white dots on a black background.  An ED refractor with flattener will easily do the job.

 

my 2 cents

Dave

[Jerry Lodriguss]

I would advise against a DSLR lens for DSO Imaging, even the venerable L series.  Using a camera lens for telephoto astronomy is a classic newbie mistake, and I can say from experience I’ve been there (10 years ago).  Reasons to avoid a lens for DSO Imaging :

Hi Dave,

 

I agree with a lot of your reasons, but man, honestly, it really doesn't matter for someone just starting out.  (and for experience ... 47 years - I win. )

 

They should go out and learn to shoot with what they have. See if they have fun doing it.  If they do, and they want to get better, then then can buy a telescope and real mount.

 

And, in the real world, and even for the most experienced and even the pros, you're going to be shooting with camera lenses anyway for shorter focal lengths for wide angles, so get used to it.

 

And the Dragonfly Telephoto Array team doesn't have any problems using 48 Canon 400mm f/2.8 telephoto lenses in their cluster that they do real science with.

 

As far as your specific points, there are some things to think about though...

 

1. I can't find a full res of M42 by tjones 84(and I looked but might have missed it), so I can't make a judgement on this. I've shot with the Canon 300/4 and I didn't find it that bad at all when stopped down a small bit.

 

2. It's really about air-to-glass surfaces in terms of light loss. The simple 70mm ED refractor will have 4 air-glass surfaces initially, but once you add a field flattener you have more than that, and a lot more elements too. And if you really want to compare a 70mm refractor with 420mm of focal length to a 300mm camera lens, you also need a focal reducer, and those are more complex and expensive, which adds to the cost which I will get to in number 3.  BTW, I recommend a small refractor like this as a first scope for astrophotography too. It's just that you don't have to go straight to a scope when you already have camera lenses that you can test at lest to see how good they are before you drop the cash on a scope and decent mount.

 

3.  Astro-Tech AT72EDII - $469 +$120 for focal reducer = $589 probably can find cheaper maybe on used forum here.

     Canon 300mm f/4 non-IS EF - $439 used on EBay.

 

    The cost is really a wash. A used 300/4 is not that expensive.

 

4. Some of them flatten the field pretty well. You are right about not being designed to shoot stars. But some camera manufacturers are now considering that when producing lenses such as the Sigma Art lenses (which cost a fortune) and Rokinon.

 

5. Much harder to use the refractor to shoot wildlife or sports. And they don't autofocus.

 

If someone said I have $450 to spend on an optical system and all I want to use it for is visual and photographic astronomy should I buy a used 300mm Canon lens or a used 72mm doublet ED refractor with focal reducer - I would unquestionably recommed the refractor.

 

If someone said I already have this 300mm f/4 lens, I would say use it, but don't expect it to be quite as good as a scope on star fields.

 

And don't forget to figure in $1,500 for the mount if you get the scope, because the line on small portable equatorial mountings like the SkyTracker and Sky Adventurere is going to be at about 300mm in terms of what they can carry,  and I'm remembering (foggily) that the 300/4 weighs a lot less than a 72mm/0.8x FR refractor.

 

Jerry

Edited by Jerry Lodriguss, 23 December 2018 - 10:12 PM.

[mvas]

A review of the Canon EF 300mm f/2.8 L USM IS ...

http://www.astropix....sts/c300mm.html

 

"... I have to admit, I was absolutely stunned at how poor the stellar images were in the new Canon 300mm f/2.8 L USM IS lens. Quite honestly flabbergasted. ... Further testing may show whether the performance improves when stopped down, but it is incredible waste of expensive glass to have to stop down lenses like these, and defeats the purpose of using such high-speed lenses ... It is more than a little disappointing that the latest Canon super-telephoto lenses, which are the flagships of their lens line, are not usable wide-open for astrophotography ..."

[Woodbridge_Dave]

Hi Jerry,

 

The original poster doesn’t own the 300 f/4 yet, so your advice to ‘use what he has’ can’t apply.

 

Also, his question was about the L version.  You won’t find that for $450 on EBay.

[2ghouls]

Also, his question was about the L version. You won’t find that for $450 on EBay.

Did you do the search? That is literally about the going price for this lens (L, but non IS) used on eBay.

My 2 cents: as others have said it is hard to find well-corrected telescope systems below 300mm FL. I’ve produced some nice images with the Canon 200mm f2.8 L. Excellent performer in narrowband, even wide open, with a m4/3 sensor. A bit disappointing in broadband. I’ve never used the Canon 300mm f/4 L non IS, but I wouldn’t write off all Canon L lenses just because of one’s experience with one in the line. Some are better than others.

[Jerry Lodriguss]

A review of the Canon EF 300mm f/2.8 L USM IS ...

http://www.astropix....sts/c300mm.html

 

"... I have to admit, I was absolutely stunned at how poor the stellar images were in the new Canon 300mm f/2.8 L USM IS lens. Quite honestly flabbergasted. ... Further testing may show whether the performance improves when stopped down, but it is incredible waste of expensive glass to have to stop down lenses like these, and defeats the purpose of using such high-speed lenses ... It is more than a little disappointing that the latest Canon super-telephoto lenses, which are the flagships of their lens line, are not usable wide-open for astrophotography ..."

 

The newer lenses are completely different and much better.

 

Jerry

[factaestlux]

As the search for a camera continues, and you are talking 300 mm lenses, I have come across a good deal with a new Nikon D5600 with an AF-P DX 70-300 mm f/4.5-6.3G ED kit lens. My dilemma is this, which might be better for DSO AP, the Nikon with the zoom, or another good deal, a Panasonic Lumix G85 micro 4/3 which I would attach to my Stellarvue SV60EDS refractor? This would go on an AVX mount and I would get an autoguider eventually. Also, how does this lens compare to the Canon 300 mm lens previously mentioned at the start?

Thanks

Edited by factaestlux, 27 December 2018 - 12:55 AM.