Nikkor 180mm vs Canon 200mm vs Leica APO 180mm
Posted 08 December 2012 - 03:07 PM
Canon 200mm f2.8
Nikkor 180mm f2.8 ED and
Leica APO Telyt 180mm f3.4
or even better any photos
Posted 08 December 2012 - 03:45 PM
Hiro has a Leica 180 and from memory said it was so sharp that it gave square stars on a 5D MKII
Canon make a 200 F2.8 that people seem happy with I didn't know they made a 180 F2.8
Posted 08 December 2012 - 03:52 PM
So I guess the sharpest is the Leica APO Telyt...which goes for about 1000 dollars..
Posted 08 December 2012 - 04:51 PM
Posted 08 December 2012 - 09:33 PM
Posted 08 December 2012 - 09:58 PM
Posted 09 December 2012 - 01:35 AM
Indeed the leica is closed more, this give eventually better result.
BUT instead of a little bit of chromatic aberration the lens do a bit flared stars at corners like my cheap plastic 18-55mm...
The 18-55 is good plastic but somewhat not better than the nikkor at F3.5, or maybe F2.8...
See leica: http://www.flickr.co...09546/lightbox/
See nikkor http://www.flickr.co...in/photostream/
See nikkor closed at f3.5? by aperture http://www.flickr.co...in/photostream/
I will certainly not pay 1000$ for a 180mm lens that doing this...
(the stars is bigger in leica too, maybe in this test the leica was not focused to details, more on color)
In this price range, I seen borg scope that do this field with focal reducer...
If I get 600$ I will buy an astrotech AT65quad! THIS give very good flat field!
My friend have one, and we are more than impress about the value of this lens/scope, the field is narrower but...
Posted 09 December 2012 - 07:27 AM
As an aside, nobody has a monopoly or super special expertise in lens design. All lens designs are compromises to a certain cost level/weight/etc. Leica also makes 180mm S lenses that go for $7k each. I expect these to be significantly better than a $1k Leica lens, especially if you stretch the format size of your sensor. I suspect that 3rd party lenses compromise further by more lax quality control, so you may be unlucky and get a particularly poor lens while everyone else raves about how great their own samples are. I am not particularly enamored by astro premium APOs either. They tend to be much slower in f-ratio than camera lenses, weigh more and if the manufacturer does not offer a matched field flattener you are up the creek. Check out my website below for direct comparos of two Canon camera lenses vs two TeleVue premium imaging APOs. They compromise on different facets, but the Canons sell in the thousands and thus have economies of scale built into their pricing. I expect that both Canon and Televue are capable of designs that can go head to head against the other, but the reality is that their markets are different, and design accordingly. You want a visual scope that can stand high magnification at the eyepiece but can be used on a smallish astroCCD? Go for an astro OTA. You want a DSLR astroimaging OTA that is hardly ever to be used as a visual scope you go for a camera lens (but you can of course always use a camera lens as a visual scope).
Posted 09 December 2012 - 09:59 AM
Thanks for your insights. I have the Canon 180 macro but have never really used it for anything. Glad to know its competent wide-open!
(because my copy always gets used at f11 to f22....)
I have an EOS-to-QHY adapter, so when the Rosette falls below my balcony roof next month, I'll try it.