Telescopes vs Tele-Lenses

Which do you use for focal length, say, between 300 and 600mm?
I am a beginner, but I tend to think (based on results taking the Moon, Jupiter, the Milky Way) that Apo telescopes are better than 'excellent' tele-lenses for Astronomy.

I use up to a Canon 800 F/5.6L on the moon. It's excellent, but it stops there. I've seen shots taken by both and from experts at that, IMO the apo telescopes beat it. Especially beyond just the moon.

Danny.

As it happens, I don’t normally use any focal length below 762mm but higher than 300mm. For 300mm I use a f/4 telephoto lens while for longer focal lengths I most often use a 762mm focal length telescope, which is a 6-inch diameter Schmidt-Newtonian that produces fairly well-corrected images without diffraction spikes not unlike those from an APO refractor. To capture wider fields of view with that telescope, I do mosaics.

Danny (and all),

I just bought an EF 800/5.6 a few hours ago. Primarily for wildlife, but I will of course point it at the stars somewhere along the way. Interested to see how it performs.

My aging Nikkor 600/4 AIS (used via a lens mount adapter on Canon bodies) definitely works well (though not perfect) on stars @ F4 with an APS-C sensor, and might be worth looking at if the OP is on a tight budget and does not mind an old manual focus lens. Otherwise, in general most modern super tele lenses work well wide open, and many older ones do too as far as I'm aware.

PS. Danny, can I ask which body you use for wildlife? I'm going to have to pick up something (crop sensor) in the next few days, and still not sure what! It does have to be a pre 2017 body though.

Yeah the moon is a very simple one to get. I use a 40 year old Canon FD 800 F/5.6L and it does well.

So these are with either the Canon FD 500 F/4.5L or the FD 800 F/5.6L.

www.birdsinaction.com/The-moon-with-teles/Moon-shots

So a larger version using the old manual focus 800 F/5.6L

That's with a Sony NEX-7 and taken in 2012. So you don't need anything fancy body wise. A 24mp APS-C body is fine. Now days I use an Oly E-M1 MKII and a FF Sony A7RIV. But yes, nothing wrong with older bodies and it doesn't have to be expensive. M4/3 would do fine, because the crop factor is already built in

Wildlife with manual focus teles using mainly the Canon FD 500 F/4.,5L on Olympus and Sony APS-C bodies .......

www.birdsinaction.com/New-Zealand-birds

All those old folders are using MF teles and older m4/3 and APS-C bodies. So again, you don't need anything fancy, although, I do like using the Sony A7RIV and the Sony 200-600 as well.

Old lenses used a, lot ..........

www.birdsinaction.com/Lenses-used/

Love using them all.

The thing is with the older bodies is that, they were darn good when they came out and nothing has changed, they are still darn good and compete with what we have today. Probably the only things that have really changed is AF speed and all the gizmo AI stuff they shove in. Otherwise, not a heck of a lot has changed except incremental benefits here and there.

All the best and I would say, going past just the moon, APO scopes would be my pick.

Danny.

I always use a lens when below 2,000mm, since that's the shortest focal length I can get from my telescope. So, I shot the solar eclipse with a Sigma 150-600C on crop (wider angle to get the corona) and a lunar eclipse on the scope on full-frame (to capture maximum light and detail).

Good stuff Danny. I have been doing much the same as you - buying older used gear/MF lenses - till now. But really struggled to focus on anything if there is any action at all involved, so have been dabbling in the dark arts (auto focus) recently, and now I've tried it with the 1DX II + 100-400, I want more!

Cost has definitely been an issue, and the saving I've made by buying used have enabled me to have a better selection of lenses/bodies than I might have done if I'd bought new. However, things are changing now, and many photogs are dumping their old AF DSLR lenses and upgrading to mirrorless lenses. So I think now is a good time to buy relatively cheap AF lenses.

For example, the asking price for the EF 800mm I bought (in great condition - I was told it had been serviced every 2 years) was £5K. New they cost £11K+. I was told the photog who's lens it was upgraded to the RF 800mm which is ~£20K new. Similar story with the 100-400 IS USM I just bought - the market is flooded with people dumping them, so I picked up a hardly used copy for a fraction the price of a new copy.

There is some talk about super-teles on Cloudy Nights, and specifically the EF 800/5.6L, which seems to perform very well wide open.

First light with the new kit:

7D II + EF 800/5.6, Gitzo 1325, Wimberly

I was going to upload here, but file size came out at a bit over 4mb for the full size image (no adjustments/editing - just highlights toned down a bit in C1P, and converted to jpg/sRGB in CS2) so I've uploaded a single exposure of the Moon here.

The vibration with the 800mm is extreme to say the least (unsurprisingly) but IS seems to compensate amazingly well (supposedly 4 stops), and images come out very sharp despite this. If I recall the exposure was around 1/1000 @ 5.6 - I will have to check.

IIRC none of my scopes I've connected a camera to are as short as 600mm (I've used 650mm/5.6, & 1000mm/11 reflectors & a 1000-4000mm refractor).
Between 300 & 600mm I typically use catadioptric camera lenses, much more convenient than connecting to a scope, this might still be the option I go for at 1000mm despite the fact my scopes are lighter than my MTO 1000mm. For astro shooting a good solid mount & relatively fast apertures are more important than for my routine shooting and the 650/5.6 would probably be the best bet, if shooting enough to make setting up worthwhile. Adding other optics (eyepiece/barlow/lens) can make this a much longer focal length upto ~3000mm seems to work quite well though it's easy to go well beyond this diffraction makes it less worthwhile.