canon 1200d. 70-300mm zoom vs SW 50 ED

[powerlord]

Apologies if it's a newbie question..I've been doing this for 6 weeks only.

So.. I have a polarie mount and an AZ GTI mount (faffing with trying EQ mode is next task), and I've been playing away focusing (sic) on M42 in various ways.

I've stuck the 1200d on the back of my skymax 102 on the az gti and though its quite cropped in, I've got some ok pics. Im consious though that the f12.75 is not ideal for this sort of thing.

I have shot with my Sony RX10iii at 600mm on the Polarie  and got some nice shots - its F4 at 600mm, but its a real pain to focus - which is very very annoying as its super low noise, amazing optics, etc.

So next I was going to try the 1200d with my 70-300mm (EF) on there - giving me 480mm at F5.6

I see a lot of folk using the Sky Watcher ED 50 for these sort of targets too. And well.. I'm not really getting the advantage that would have over the canon zoom ? F is about the same, you lose aperture options, and without an FF you get blurry edges. So - what am I missing ? What are the advantages of using a small refractor/spotting scope with a DSLR over a camera lens basically ?

stu

[happy-kat]

The skywatcher FF for the 50 ED does not work with a mirrored dslr and it might still be a bit short on back focus for your Sony.

If you already own the lens then I'd try using it. If using a camera lens it might be great for photography but stars are challenging on optics.

Edited February 21, 2021 by happy-kat

[powerlord]

Sorry yes - I wasn't suggesting 50ED +FF for that reason. I was pointing out the lack of a need for an FF with a camera lens.

Sony - I can't do anything with the scope - the lens is not removable.

Ill see how I get on with the canon. I did try the sony vs canon @ 300mm on the moon - and the canon had pretty bad chromatic abervations vs almost none on sony.

So, I imagine one positive as you say, is the optics of an ED type scope are superior for distance work like stars/DSO than a cheap kit lens.. it's a pity as you say the FF doesn't work with it and a DSLR.  hmm.

[alacant]

1 hour ago, powerlord said:

70-300mm (EF) on there - giving me 480mm at F5.6

Hi. Yeah, try it.

I've the cheepo 75-300 ef which apart from being difficult to focus manually, is a no go for ap at anything much above 75mm.

The 70-300 is much better quality so you maybe pleasantly surprised but bear in mind that at 300mm, it still gives you a 300mm lens, not 480mm.

Cheers and good luck.

[powerlord]

Mine is the tamron 70-300. Ef. So on the 1200d it's effectively 480. The ef-s Canon jobs were too expensive.

[happy-kat]

On the 1200d it still gives you 300mm.

The magnification is as 300mm but the field of view that the 1200mm sensor captures is as 480mm using that lens.