Galaxe 520mm vs Sigma 500mm for Canon 450D: Questions. (1 Viewer)

Greetings! I am one of many amateur birders/bird photographers mulling over buying a sigma 500 mm lens (for around $1k) or a 520mm galaxe spotting scope (http://www.galuxe.com.tw/telescope_GS520_801.html, about $400-500 not including the adaptors) to pair with my Canon 450D.
There are several lingering questions that I have after reading through what feels like a million digiscoping pages. I apologize in advance for knowing that these are questions that have been answered elsewhere on the internet, but I have had a hard time finding the answers.
1). Does anybody have any opinion about Galaxe scopes? They're from Taipei, where I currently live, and so affordable.
2). What would a 520mm spotting scope equal for a telephoto lens for my crop-censored DSLR?
3). When using a spotting scope with a DSLR, how quickly can you change between the two? Is it the sort of thing that I can be using the spotting scope for birding, decide I want to take a photo, and then boom, be firing off shots? Or is it a slower process? The speed of a long lens is always attractive to me, and a lot of my best shots thus far have been spur of the moment.

Thanks for any info on any of the above questions!

This is an astro scope used for prime focus photography and you can pick up a lot of info on this type of photography in the 'astro scope for bird photography forum' here. http://www.birdforum.net/forumdisplay.php?f=657

I couldn't find out much about the scope you are looking at, especially the type of glass used which is most important. I use a Canon 450D on a 600mm Skywatcher 80ED telescope, see my gallery link. Swapping over to spotting scope mode would be pretty quick, maybe 10 seconds.

The crop factor figure is just the lenght of the scope multiplied by the camera crop factor. 520x1.6=832

Paul.

I found some other scopes the same as this one but with different names. As with a lot of scopes like this they get rebranded under different names. The scope is made by a company called Longperng in Taiwan.

You can find it as Longperng 62, Scopos Observer 62 and Revelation 62mm Achromatic Refractor, all are 520mm 4 element designs and very likely all are the same scope, they certainly all have the same telescope body and focuser. With the 4 element design, the second two elements are to give it some field flattening qualities as shorter scopes like this can suffer with field curvature. You could use the two names above to try and find some reviews on what it's like with regards to chromatic aberrations. It doesn't use any fancy glass so it may suffer with this problem. ED low dispersion glass is the preferred choice for photography.

Paul.

Thanks Paul. You certainly have some great results! I guess I didn't realize this was an astro scope because of all the pictures of birds. Translating the page, it seems they are selling it as a "dual use" scope for wildlife and astro. Is that normal? Digiscoping for wildlife seems to be their focus (Taiwan is really into bird photography, but alas, most info is in chinese), so that seems promising. And I'm not sure I want to spend more than the $600 or so I would on this for a scope, because at that point I think I would start looking at lenses. In any event, your information is very appreciated.

A telescope will beat an equivalent length camera lens by a good margin and generally a scope is a lot cheaper. Also telescopes will take teleconverters without any loss in detail but if you use teleconverters on camera lenses the results are quite soft. Telescopes are manual focus and fixed aperture so the only real benefit to a lens is the auto focus.

Astro scopes generally come with some sort of prism so that you can use eyepieces so that's quite normal. As a camera lens you take the prism off so it's quite quick to switch between eyepiece viewing and photography modes.

Paul.

Paul Corfield said:

A telescope will beat an equivalent length camera lens by a good margin and generally a scope is a lot cheaper. Also telescopes will take teleconverters without any loss in detail but if you use teleconverters on camera lenses the results are quite soft. Telescopes are manual focus and fixed aperture so the only real benefit to a lens is the auto focus.

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So you are saying that a telescope that is designed for viewing rather than photography will give better results than a lens which is specifically designed for this use? Any chance of some examples to back this up as if it is true it would be time to start looking at scopes.

postcardcv said:

So you are saying that a telescope that is designed for viewing rather than photography will give better results than a lens which is specifically designed for this use? Any chance of some examples to back this up as if it is true it would be time to start looking at scopes.

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I have been looking at a lot of DSLR - astroscoping stuff lately and have been very impressed with results. I am just about on the point of having a crack at it myself. Big draw back is that you use manual focussing but to be able to get a 600mm scope/lens for less than 10% of the cost of a 'big white' is certainly attractive.

postcardcv said:

So you are saying that a telescope that is designed for viewing rather than photography will give better results than a lens which is specifically designed for this use? Any chance of some examples to back this up as if it is true it would be time to start looking at scopes.

Click to expand...

Buried deep in the astro scope forum is a link to a side by side comparison. I tried to find it a while ago but after an hour of digging around I gave up. The photographer had a 600mm telescope set up alongside a Canon 600mm lens to photograph the same target. The photographer also used a Canon 1.4X and a Canon 2X teleconverter on both scopes. Photos at the native 600mm were the same, once the TC's were used the Canon lens was softer at 1.4X and then softer some more at 2X. The scope still stayed very sharp with a TC added and the lens was a clear 2nd place with the TC's. I take my own scope up to 5X with virtually no loss to sharpness. That's a specialized area though with regards to light, shutter speed etc. In reality 2X is enough and more often than not 1.4X is all that is needed on a 600mm scope.

Paul.