[AstroJason (Jason)]

Originally Posted by Camelopardalis

Jase, the difference in FOV is only 15% by diameter, so not a huge difference.

Whether or not either it's a good fit depends on what targets you're aiming for.

Yeah not a huge difference I suppose when comparing the 400mm Lens to the Star71 but I think I prefer the doubling of focal length. Well you know the targets I am after! Wide field Dark Nebulae!

Originally Posted by hotspur

just buy the canon 400 mm F 5.6 I've owned one for years and it does everything you want very well and more.Even bored at work the other day I used the 400 mm for half an hour and nailed a cover image for outdoor magazine,see image,and its earned another $250 for little effort.Its a light easy to use lens,last night used it to image the current comet.(see other thread)

Thanks for sharing your shot Chris. Congrats on getting the cover image of a magazine too. Its a very sharp image, bang on the rabbits eyes and even the bokeh looks good. I saw your comet shots, seems to give the reach I am after that my 200mm lacks.

Originally Posted by raymo

I'd get the Skywatcher Esprit 80 ED. Same focal length [ 400mm f/5]
as the lens, but slightly faster, and much more versatile,[ who knows, you could even look through it sometime]. and more light grasp than the WO 71.
raymo

Cheers Raymo for your input, I agree that it would be a great option for one it is faster than the lens but as Dunk pointed out the imaging circle is on the small side and I would definitely need to crop my images a bit to remove the huge amount of vignetting.

Originally Posted by killswitch

Tough choice Jase

With the Star71, focusing is easier and you can lock it.

But the 400mm can also be used for daytime.

Yeah mate, it is a tough choice but I am enjoying the researching part of this. I guess the focusing would be easier considering it has a dual speed focuser as well as being able to lock the focus. And yes the lens could be used for daytime photography, plus its light so I could probably carry it around with me on hikes, etc. Hmm decisions, decisions.

Originally Posted by Camelopardalis

Unfortunately, the Esprit 80 only has a 33mm flat imaging circle, which is fine for APS-C but less great for the bigger sensor in the 6D. That's one of the reasons I ended up "upgrading" to the Esprit 100, as the imaging circle is 40mm, almost enough for a full frame with a tiny bit of cropping, but the focal length is a little longer at 550mm.

The Star71 seems to be pretty unusual in that it's supposed to be flat across a whole full frame sensor and be short focal length.

Nothing stopping you using it for daytime of course, although I'd expect it's a little heavier than the Canon lens

Cheers mate, yes I noticed the imaging circle was too small for a full frame chip. Its a real shame as I would obviously have gone for the Esprit 80 being f/5. All good, I am not exactly in a super rush to pull the trigger yet, just gives me time to do some more research to make a better educated decision.