Originally posted by MossyRocks: I think on that Sigma 300/4 the focus goes the we we are use to, but with astro it isn't a big concern.
Those old lenses are much lighter than modern ones so the 200/4 would be a light lens even with the metal lens barrel, the 200/3.5 wasn't much more weight wise. However my sigma 300/4 with more elements outweighs either of those 200s.
So the Sigma does! I actually was watching one on eBay...it went for $172, which seems a steal of a price. I unfortunately missed the final minutes.
Originally posted by Lew Dite: If you restrict yourself only to lenses that perform well on stars when used wide open, your selection will be very small. And none of them to my knowledge are likely to be vintage lenses.
That Takumar Ultra-Achromatic 300mm f/5.6, despite its high used price and use of two fluorite elements, is not necessarily going to be the cat’s meow wide open. CA will likely be quite low but there is no way to know how well it corrects other aberrations when wide open. (Astrophotos taken with it, much less ones taken at full aperture, are rare as hen’s teeth.) Its high price likely merely reflects its rarity.
Furthermore, any assumption that a lens at a given fully-open aperture should perform at least as well as a larger lens that is stopped down to that aperture (not saying you made this assumption, but I have heard it before) is easily refuted by the number of lenses for which that is not true.
For example, I have the SMC Pentax-M 50mm f/2 lens. I also have the SMC Pentax-A 50mm f/1.4. When the latter is stopped down to f/2, it absolutely trounces the former lens for AP. And while the f/1.4 lens is a little heavier and larger than the f/2 lens, the difference is not enough to matter in the least (because they are both small lenses).
Re weight, note that the aforementioned SMC Pentax-M* 300mm f/4 is the same weight (825g) as the Takumar Ultra-Achromatic 300mm f/5.6. Given that the M* is said to be very sharp at f/5.6, there is a chance that it is as good or maybe even better at f/5.6 than the Ultra-Achromatic. At roughly 1/10th the price, it is certainly WAY cheaper.
I have a tendency to jump for glass that's good wide open - Zeiss 35/2, Macro-Takumar 50/4, Samyang 135/2, and now the Voigtlander 180/4. I agree they're rare, and not always necessary - I've got a Pentax-A 50/1.2 and FA77 that don't need to be sharp wide open to be awesome.
I think you're right on the A* 300/5.6, the price is likely not justified.
I'm not arguing that a 50/2 @ F4 is as good as a 50/1.4 @ F4. That's why I have an A 50/1.2
It's really when the lenses get longer that I get concerned over the quality to weight ratio. There's the "is it going to wind up in my bag" factor, and there are plenty of cases where the slower aperture lenses win in the quality/weight contest.
I like your example on the weight of the 300/5.6 - you're right that aperture itself isn't the metric, it's quality to weight. It's correlated to aperture, but not defined by it. I do think I'm going to try to find an F* 300/4.5. Seems like a nice compromise, and the AF can be useful at times with these longer lenses.
Originally posted by MossyRocks: I've found the same with my S-M-C 50/1.4 Takumar vs my SMC A 50/1.2 where the 50/1.2 is better/sharper at 1.4 than the 50/1.4 is. I will run both of them at 2.8 for astro shooting as they are really good. Having seen shots of someone who used the new DFA * 50/1.4 if it is better at 2.8 for astro it isn't by much. I was actually really surprised that it wasn't a lot better given that it is a new modern lens with modern coating, a modern design, and a pile of elements.
As far as looking for a great lens wide open there are very few. You have one with is the samyang/rokinon 135/2 UMC and there are very few lenses that perform like that wide open. Two that come to mind that I also own are the SMC A* 400 f/28. ED [IF], and Laowa 12mm f/2.8 Zero-D. In all cases however to get perfect shots they all need to be stopped down, with the 400/2.8 needing the least (I run it at f/3.5) and the 12mm and 135mm needing a bit more. If looking for something around 200-300mm that is really good wide open why not see if you can find a u
sed Williams optics 250mm f/4.9 scope. If someone had one of those Ultra-Achromat takumars I would love to give them a try for astro shooting just to see how they perform but so far no one has wanted to loan one out for a few weeks.
I see you picked up an A* 400, congrats Mossy that rocks! I'm glad to hear you're enjoying it.
Dude, great suggestion on that Williams 250/4.9 scope. That's pretty slick. I love the included bahtinov mask, it's a great compact complete package. A bit on the heavier side, but mighty tempting. Have you used one before?
