NGC3766 at 300mm and 1800mm focal length

[avandonk]

These images were done at last new Moon. Both taken with the Canon 5DH.

Canon 300mm F2.8L image 1.4MB
http://members.optusnet.com.au/~cheekyfish/300f_L.jpg

TAL200k at 1800mm F9 image 1.2MB
http://members.optusnet.com.au/~cheekyfish/1800f_L.jpg

Bert

[h0ughy (David)]

certainly puts some perspective on things

[avandonk]

Here is exactly the same area from both images. Gives you some idea how longer focal lengths at larger apertures are definitely better. Although I think the Canon lens does remarkably well especially considering the huge field of view it captures.
This is just something to do with cloudy skys. Thought it may be of interest.

Bert

[Ingo]

Nice images

Put your 300 F2.8 on F4 see if there's a difference. It also doesn't look focused right.

[iceman (Mike)]

The large versions are excellent, Bert. The attachments suffer too much from jpeg compresison artifacts.

Lovely clusters, well done.

[avandonk]

Ingo a Canon 300mm F2.8L is as good at f/2.8 as it is at f/8! The only difference is a very slight astigmatism at the corners on full frame cameras at F/2.8. and is only noticeable on very bright stars.

We are comparing a 300mm focal length F/2.8 lens to a 1800mm FL f/9 mirror optic. I can assure you focus was spot on in both cases. The TAL 200k has an aperture of 200mm diameter compared to the lens of 105mm diameter.

Thanks for even thinking about the differences, it has been a comparison I have been meaning to do for a while.

Bert

[Dr Nick (Nick)]

Nice, very pristene and sharp!

[Ingo]

Originally Posted by avandonk

Ingo a Canon 300mm F2.8L is as good at f/2.8 as it is at f/8! The only difference is a very slight astigmatism at the corners on full frame cameras at F/2.8. and is only noticeable on very bright stars.

We are comparing a 300mm focal length F/2.8 lens to a 1800mm FL f/9 mirror optic. I can assure you focus was spot on in both cases. The TAL 200k has an aperture of 200mm diameter compared to the lens of 105mm diameter.

Thanks for even thinking about the differences, it has been a comparison I have been meaning to do for a while.

Bert

Yeah, I thought the 300 F2.8 would be sharp as heck even at F2.8. It's the same with my 300 F4. The sharpness doesn't even increase stopping it down.

[tornado33]

Yes it sure shows the quality of these lenses. We can virtually call them portable Schmidt cameras
Scott

[Ingo]

I've used a Nikon 400 F2.8 AF-S II...it's so heavy. I had to hold it by the tripod collar mount otherwise I'd have ripped the mount right off my D200. I definitely couldn't carry that thing around. I'd need use my monopod. They're hell of lenses, can't get any sharper wide open

Too bad they're priced that much

[glenc (Glen)]

Thanks Bert. great images.

[Garyh]

Very nice Bert...both nice images!!!! the 300mm lense does a nice job even with the crop of the cluster. But its like comparing apples and oranges with the different focal lengths, same like comparing the 300mm to a 50mm lense.
Well done!!
cheers

[bluescope]

Canon L series lenses are simply the best in their class hence the high price tag but they are well worth the expense if you want superb optics ...

[Ingo]

Originally Posted by bluescope

Canon L series lenses are simply the best in their class hence the high price tag but they are well worth the expense if you want superb optics ...

I wouldn't say there's a difference besides that Nikon only has VR in the 300mm and not the 400mm, Canon has IS in the 300-600 range. NASA uses Nikon Telephoto lenses in space with Kodak-Nikon bodies.

[bluescope]

It's a bit like Ford versus Holden ay ! Both good !

Whoops, sorry just realized your from the States and probably don't get that comparison !