Re: Countless prime lenses, why no F4/F5.6 telephoto primes?
aCuria wrote: Knut. wrote: aCuria wrote: Knut. wrote:
GM or Apo-Lanthar type lenses:
135/f4 (<450g)
150/f4 (<500g)
180/f4 (<500g)
200/f4 (30% lighter than the zoom)
300/f5.6 (~ 700g)
All of these are on my wishlist!
70-200/4 gets you the first 4, and a 1.4x gets you the last one
30% lighter means you save 200g, but you lose all the other focal lengths. Is that worth it?
That new 100-400/4 could be interesting
At 1) Yes, but a single focal length is always much lighter. I want my lenses as light as possible and do zooming in post (e.g. I crop). To me (of course a very personal view) zooms are obsolete and a relict of times when I was still shooting slide film. Today I can do all necessary zooming by cropping in post, up to crop factors of 1.5 or even 2.
2) Personally I find light weight most important. Since I can crop, I also do not lose anything. Long ago I have noticed that 24MP is more than enough for anything I do. The reserve I have between 24 and 50(60)MP is what I can divert to cropping.
A reason why my lenses are usually spaced with a factor of 2x fov. With a dedicated button I do the 1.4x croppings for in between focal lengths.
14-35-75-150 for example (cropping with a factor of 1,4 on an A7RV) would also yield 24, 50, 110, and 230.
This yields 14-24-35-50-75-110-150-230 in a light weight four lens package with at least 30MP; what more to ask?
In my view its the subject that determines if a prime or zoom should be used. A 100-400mm f/4 is going to be much more useful for sports compared to a pair of 100/4 and 200/4 primes.
I am not convinced the cropping angle works so well in the context of slow primes either. If we start at 100mm f/4 and crop to 200mm you end up with f/8 equivalent, this is too slow for my taste.
It makes more sense when starting at 35/1.4 and cropping to get 70/2.8 equivalent.
I complete agree with you, that zooms are very useful for sports. I also have a 200-600 zoom and cannot really imagine replacing it with fixed focal lenses.
What I wrote was from my perspective which is dominated by landscape shooting. For landscapes I always do some fine tuning with cropping and (to me) this is best done in post. I agree that in most cases this does not exceed a crop of 1,5 so I‘m mostly fine with lenses spaced at 2x. I have no problems finding exactly the focal length I need between 9mm and 100mm, but field is very thinned out above that. and I personally miss light weight lenses (<500g) there.
I did not fully understand your argument, why a 35/1.4 is a 70/2.8 when cropped. Maybe you can explain what you mean?
In any case I shoot most of my lanscape shots at f5.6 or f8 so for (my) specific use a slow but very sharp fixed focal length between 135 and 200mm would be very interesting. If it were just 400g (e.g. 150 or 180mm, f5.6 should be doable with 400g), I would just drop it in my carry on bag more frequently (much much more often than I take the 1kg zoom).
Nov 04, 2025 at 04:38 AM
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