price difference of f/1.4 Vs. f/1.8 ?
Dec 9, 2011 04:13:41 #
Roger Hicks
Loc: Aquitaine
Diminishing returns. Faster lenses are a LOT harder to make sharp: you need more glasses, more complex designs, tighter build control. There have been lenses which were only 'stretched' designs of slower lenses (similar, but faster) and quality was frankly poor with the faster lenses. Meyer's 50/1.9 Primoplan was a good example. So was Canon's 50/0.95.
Assuming state-of-the-art designs (at any given period) the slower lenses are normally better: sharper, contrastier, more even illumination... In that case, the only reason to buy the faster lens is when you want the speed.
At one time I had both 35/2 (Summicron) and 35/1.4 (Summilux) lenses for my Leicas. Both were about equal by f/5.6. but the Summicron was slightly better at f/4, significantly better at f/2.8 and much better at f/2. On the other had it was no use at all at f/1.4 because f/2 was the maximum aperture. This is why I still have the Summilux but not the Summicron.
Then again, the design of the slower lens is sometimes some way from state-of-the-art, assuming it is designed to be sold cheaply, and that's before you start saving money on the mount, materials, number of leaves in the diaphragm, etc., and as others have remarked, there's the fact that fast lenses are of limited appeal, so economies of scale are less. For a REALLY fast lens (50/1) look at http://www.rogerandfrances.com/subscription/ps%20king.html.
Of course, f1.8 to f/1.4 is 2/3 stop, not 0.4 stop. For an overview of lens design, speed, the meaning of stops, etc., along with examples shot with a wide range of lenses (14mm to 800mm, and with f/1.2 to f/11 maximum apertures), see http://www.rogerandfrances.com/subscription/ps%20basics%20lens%20design.html
Cheers,
R.
Assuming state-of-the-art designs (at any given period) the slower lenses are normally better: sharper, contrastier, more even illumination... In that case, the only reason to buy the faster lens is when you want the speed.
At one time I had both 35/2 (Summicron) and 35/1.4 (Summilux) lenses for my Leicas. Both were about equal by f/5.6. but the Summicron was slightly better at f/4, significantly better at f/2.8 and much better at f/2. On the other had it was no use at all at f/1.4 because f/2 was the maximum aperture. This is why I still have the Summilux but not the Summicron.
Then again, the design of the slower lens is sometimes some way from state-of-the-art, assuming it is designed to be sold cheaply, and that's before you start saving money on the mount, materials, number of leaves in the diaphragm, etc., and as others have remarked, there's the fact that fast lenses are of limited appeal, so economies of scale are less. For a REALLY fast lens (50/1) look at http://www.rogerandfrances.com/subscription/ps%20king.html.
Of course, f1.8 to f/1.4 is 2/3 stop, not 0.4 stop. For an overview of lens design, speed, the meaning of stops, etc., along with examples shot with a wide range of lenses (14mm to 800mm, and with f/1.2 to f/11 maximum apertures), see http://www.rogerandfrances.com/subscription/ps%20basics%20lens%20design.html
Cheers,
R.
Dec 9, 2011 06:28:13 #
There are times, when I read all the comments, I beging to believe this is a brag board. Mine is bigger,faster, etc. I know I'll catch some flack over this, but go back and read all the comments.
Dec 9, 2011 07:23:20 #
Roger Hicks
Loc: Aquitaine
BillyDuds wrote:
Fascinating discussion! Can someone please explain how it works if both the 1.4 and the 1.8 lenses are set at an identical aperture (1.8 for example), the depth of field with the 1.4 is shallower, resulting in better bokah? It seems logical that the DOF with the 1.4 lens set wide open at 1.4, is shallower (better bokah) than the 1.8 lens wide open at 1.8. But if both lenses are set at 1.8? Why is the 1.4 lens still superior?
D-o-F is identical at a given aperture for a given focal length, and a wider aperture doesn't give you 'better bokeh': it just gives you a shallower depth of field.
Cheers,
R.
Dec 9, 2011 08:33:40 #
Best to go to the camera store with your camera and try both lens in the store to see how much lower you can go with the 1.4 than the 1.8. If the difference is that much more in your opinion, then you have your anwer. If in your opinion the difference is not significant, get the 1.8.
Dec 9, 2011 08:33:50 #
Best to go to the camera store with your camera and try both lens in the store to see how much lower you can go with the 1.4 than the 1.8. If the difference is that much more in your opinion, then you have your anwer. If in your opinion the difference is not significant, get the 1.8.
Dec 9, 2011 12:52:58 #
FrankKello wrote:
Best to go to the camera store with your camera and try both lens in the store to see how much lower you can go with the 1.4 than the 1.8. If the difference is that much more in your opinion, then you have your anwer. If in your opinion the difference is not significant, get the 1.8.
I'm thinking that differences will show up on a large monitor at full size and not on the camera small screen.... making it a hard hard call in the store.
I'd first rely on an in depth study such as as the excellent one Adorama has at: http://www.adorama.com/ALC/article.aspx?alias=50mm-lens-shoot-out-f18-or-f14&utm_source=ET&utm_medium=Email&utm_campaign=EmailALC111711
and then try them out it at a brick and mortar store to confirm.
Dec 9, 2011 16:37:23 #
Danilo -- many thanks for the very informative answers to my question. Hope I can retain all that until I can get a nice fast prime!
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