200mm lens

[multiweb (Marc)]

Hi guys, I'm after a lens to image in the 200mm FL ball park. For astro only. What would you recommend based on your experiences? I have a Pentax adapter (K mount I think). Thanks.

[Octane (Humayun)]

It's hard to best the Canon EF 200mm f/2.8L II USM. Under $1K. Get yourself a K to EF adapter off eBay.

H

[DavidU (Dave)]

Marc, these are very nice but rare. They have an 18 blade iris so the diffraction spikes are minimal.
There are many 200mm f/4 Takumar lens's avail aswell.
http://www.ebay.com.au/itm/M42-TAKUM...item4cf75f3501

[space oddity]

The Takumar 200mm f/2.5 should not cost an arm and a leg. Given it will probably be used wide open, number of diaphragm blades, being a screw mount or being manual aperture only is of no consequence. The Pentax 200mm f/4 , although slow, will be plenty sharp enough(and cheap). With astro, best to avoid zooms for 3 reasons.They are slow, sharpness not as good and extra elements lead to internal flare issues.Screw mount lenses are cheap and can be adapted to basically all lens mounts. Needless to say nothing automatic is going to work.

[Waxing_Gibbous (Peter)]

Originally Posted by DavidU

Marc, these are very nice but rare. They have an 18 blade iris so the diffraction spikes are minimal.
There are many 200mm f/4 Takumar lens's avail aswell.
http://www.ebay.com.au/itm/M42-TAKUM...item4cf75f3501

Blimey!
Just the lens I was going to recommend.
That's a decent price BTW and the seller is a bricks and mortar shop that's quite famous in the UK.

As you don't need EF or IS the world's your Oyster really Marc.
Apart the Takumars there's:

Canon FD 200 or even 300 2.8 FDs

Olympus or Rollei glass - not an expert on the different FLs, but both companies produced excellent, flat - field lenses.

Nikon MF lenses as well but they might be a tich more expensive as they will still fit the digital bodies.

Leica lenses are likely to be pretty dear, but their colour correction is esentially perfect and they are almost too sharp.

That's all that spring to mind here.
G'luck!

[bojan]

http://www.iceinspace.com.au/forum/s...ighlight=200mm

[multiweb (Marc)]

Thanks for all the info guys. I'm on a budget, still testing the waters and learning so I ended up getting an auction from eBay late last night. A bit of a spur of the moment. It's a Pentax M 200mm f4 lens.

[DavidU (Dave)]

Nice one Mark. This image was done with a Takumar 200mm @ f/4
http://www.diana.dti.ne.jp/~show-g/ic1396.jpg
http://www.diana.dti.ne.jp/~show-g/ic2177.jpg

[multiweb (Marc)]

Looks pretty cool. Mine's shipping as we speak from Tokyo - Japan. Should get it in a couple of days. Can't use it with all those clouds now anyway. Next week looks pretty damp too.

[gregbradley]

I know its late to post.

I have used Nikon 180mm F2.8 ED and Canon 200mm FD.

Both were good. All need to be stopped down really. Lenses generally are not as well made as scopes. Pentax 67 300mm EDIF is the best.
Also rare and expensive (US$2000).

It depends on the CCD. The larger the CCD the more particular you will have to be.

I am now using Pentax 67 F4, 55mm, 165mm and 300mm.

I used the 55 on the weekend and it was good but some aberrations in the right side with the Proline 16803 (44mm square chip). Stopped down to F8 and binned 2x2 looked pretty good.

I did not use the others yet.

Greg.

[multiweb (Marc)]

Originally Posted by gregbradley

I am now using Pentax 67 F4, 55mm, 165mm and 300mm.

How's the field with the 165mm?

Tried the 200mm last night, one stop down ( nearly fully opened) and I had a very good field, flat to the corners with no aberrations. It pretty much worked out of the box surprisingly. Found focus, etc.... The built-in telescopic hood is also very convenient. I didn't have to use any dew heaters. Although it was very windy and dry with bad seeing and a blazing moon I managed to do 7h worth.

Love the field and image scale. I got a shot around the prawn extending from all the surrounding clusters back o the dark tower with enough details to zoom up close. Going for seconds tonight and I'll have some good stuff to process soon.

[Max Vondel (Peter)]

Yes the SMC 200F4 is a fun lens.
Keep an eye out for the SMC200F2.5
sometimes you can score a bargain!

I recently got an SMC135F2.5
but the weather been too @^#& to take it out!

[gregbradley]

[QUOTE=multiweb;733789]How's the field with the 165mm?

I don't know yet, I haven't used yet. I've only used the 55mm F4 and that had to be stopped down a few stops (about F8 I think) and binned 2x2 then it was good.

I have the 165 and the 300mm F4.

What camera are you using?

Greg.

[multiweb (Marc)]

[QUOTE=gregbradley;734915]

Originally Posted by multiweb

How's the field with the 165mm?

I don't know yet, I haven't used yet. I've only used the 55mm F4 and that had to be stopped down a few stops (about F8 I think) and binned 2x2 then it was good.

I have the 165 and the 300mm F4.

What camera are you using?

Greg.

I'm using the QHY8. That's 6MP about 28mm diagonal. Like the *istD I've got.