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A thing I have with photography is this obsession with very low F#’s as being better A low F# is hard to produce but it doesn’t always make for a high quality

A thing I have with photography is this obsession with very low F#’s as being better A low F# is hard to produce but it doesn’t always make for a high quality image. These lenses have large ROC and allow very high angle rays to enter the system. So there is often significant aberrations in these lenses.

anta40 7y ago
Kinda reminds me to the legendary Canon 50mm f/0.95. Manual focusing at f/0.95 is not that easy and with that reaaallly shallow depth-of-field, making interesting composition is hard.
- geerlingguy 7y ago
  The 'NIKKOR Z 58mm f/0.95 S Noct' is Nikon's answer to that, and yeah, it is difficult to nail focus when you have a depth of field for close subjects that's in fractions of millimeters!
- jungletime 7y ago
  You might like this video on ultra fast lenses. https://www.youtube.com/watch?v=2p5E7iXxeQE https://www.youtube.com/watch?v=2p5E7iXxeQE At the end they compare budget lenses like the Canon 50mm f/0.95 and find that the SLR Magic 25mm T0.95, seems to work better in low light.
xyzzy_plugh 7y ago
Why is this strange? A low f-stop IS better because it let's more light in, meaning I can record more information using my sensor in less (shutter) time, resulting in sharper images (less shakiness/improved stabilization). There are lots of things that can remedy higher f-stops to some extent, but nothing really substitutes that big aperature. The big appeal if low f-stop lenses from high end lensmakers is that they have reduced aberrations/distortions because they use a shit ton of glass to improve the image, which in turn is why they can be so incredibly expensive. A $50 f/1.6 is going to be dogshit. The $5000 lens is going to have additional optics to remedy the large ROC and high-angle rays. The trade-offs are often worth it.
- ashtonkem 7y ago
  Faster lenses are more flexible, whether or not that flexibility is worth the added cost and weight depends on your intended use case. A lot of photography gets done stopped down to f/8 or so, after all.
- pdpi 7y ago
  A fast f-stop is better only if it allows you to use a lower ISO or a faster shutter speed in a context where you need a fast shutter. And even then, with modern cameras with good IS and strong low-light performance, you might still be better off with a slower f-stop. Everywhere else, most lenses are sharped stopped down to the f/5.6–f/8 range, and depth-of-field is an entirely stylistic choice — e.g. shallow dof is popular with portraits, but largely undesirable for landscape photography.
  - snowwrestler 7y ago
    One thing that drove lust for low f-stops is that the lens had to be engineered and built to a higher degree of precision to produce acceptable quality fully open--which also benefited people who stopped it down. For a long time a f2.8 lens stopped down to f8 was likely to produce a better image than a f4 lens stopped down to f8--simply because the f2.8 was built better. That is no longer necessarily true. For example in Nikon world the current 70-200mm f4 is generally thought to have the same quality as the 70-200mm f2.8. Lens quality in general has gone way up as digital cameras have exceeded the resolution of film. Now companies have to engineer even mid-range lenses to produce very high-quality images since even mid-range DSLRs might have 20MP sensors or more. And on a computer it's easy to zoom in and pixel-peep... and share your disappointment with everyone else if the lens is bad. For all the legend-making around the Nikon 300mm f2.0, their latest 300mm f2.8 is going to outperform it in every way expect for the number of photons it lets through.
    - pdpi 7y ago
      > even mid-range DSLRs might have 20MP sensors or more. This is actually a funny thing. The APS-C Canon 90D has a slightly higher resolution sensor than the full frame 5Dmk4, and significantly higher than the brand new, also full frame, 1DXmk3. Sony’s APS-C bodies are all 24MP, the same as the a7iii and the flagship a9/a9ii. Other than dedicated high-res models (5DS, a7R, D850/Z7), high-end cameras routinely have much lower pixel density than cheaper cameras, because resolution doesn’t matter that much for most applications, and pros care for a whole bunch of other features that scale poorly with resolution (such as low light performance and buffer drain speed)
ska 7y ago
The focus on f-stops was/is for the same reason people chased high ISO film in the old days, and "ISO" on sensors now, and the focus on extremely long tele's also. This isn't about getting the best image possible but about capturing something you otherwise couldn't get at all. All of this gear is about flexibility to handle poor lighting conditions, things moving quickly, etc. If you are product photographer with a room full of lighting equipment you are going to pick the right lens for the job and make the room work. Other people rarely have this freedom. It's worth noting that in the last couple of generations of digital sensors, we're objectively in a better situation than fast film was, so that loosens the need for fast glass a bit. The same is true for widely deployed mostly ok physical image stabilization systems.
- ip26 7y ago
  Bird photography is my personal example. If you go back ten or twenty years, you quickly notice much of the bird photos of the age have no background- because high power flash was mandatory. But today, while it is a challenge, it is possible to photograph small subjects handheld in natural light- with the latest & greatest equipment.
farazbabar 7y ago
Some of these lenses are quite amazing. My favorite lens from this class is the leica noctilux at f0.95. It is tac sharp even at f0.95 (if you can nail the focus) and the images make even an amateur like me look like a photo god.

anta40 7y ago

Kinda reminds me to the legendary Canon 50mm f/0.95. Manual focusing at f/0.95 is not that easy and with that reaaallly shallow depth-of-field, making interesting composition is hard.

geerlingguy 7y ago
The 'NIKKOR Z 58mm f/0.95 S Noct' is Nikon's answer to that, and yeah, it is difficult to nail focus when you have a depth of field for close subjects that's in fractions of millimeters!
jungletime 7y ago
You might like this video on ultra fast lenses. https://www.youtube.com/watch?v=2p5E7iXxeQE https://www.youtube.com/watch?v=2p5E7iXxeQE At the end they compare budget lenses like the Canon 50mm f/0.95 and find that the SLR Magic 25mm T0.95, seems to work better in low light.

xyzzy_plugh 7y ago

Why is this strange? A low f-stop IS better because it let's more light in, meaning I can record more information using my sensor in less (shutter) time, resulting in sharper images (less shakiness/improved stabilization). There are lots of things that can remedy higher f-stops to some extent, but nothing really substitutes that big aperature. The big appeal if low f-stop lenses from high end lensmakers is that they have reduced aberrations/distortions because they use a shit ton of glass to improve the image, which in turn is why they can be so incredibly expensive. A $50 f/1.6 is going to be dogshit. The $5000 lens is going to have additional optics to remedy the large ROC and high-angle rays. The trade-offs are often worth it.

ashtonkem 7y ago
Faster lenses are more flexible, whether or not that flexibility is worth the added cost and weight depends on your intended use case. A lot of photography gets done stopped down to f/8 or so, after all.
pdpi 7y ago
A fast f-stop is better only if it allows you to use a lower ISO or a faster shutter speed in a context where you need a fast shutter. And even then, with modern cameras with good IS and strong low-light performance, you might still be better off with a slower f-stop. Everywhere else, most lenses are sharped stopped down to the f/5.6–f/8 range, and depth-of-field is an entirely stylistic choice — e.g. shallow dof is popular with portraits, but largely undesirable for landscape photography.
- snowwrestler 7y ago
  One thing that drove lust for low f-stops is that the lens had to be engineered and built to a higher degree of precision to produce acceptable quality fully open--which also benefited people who stopped it down. For a long time a f2.8 lens stopped down to f8 was likely to produce a better image than a f4 lens stopped down to f8--simply because the f2.8 was built better. That is no longer necessarily true. For example in Nikon world the current 70-200mm f4 is generally thought to have the same quality as the 70-200mm f2.8. Lens quality in general has gone way up as digital cameras have exceeded the resolution of film. Now companies have to engineer even mid-range lenses to produce very high-quality images since even mid-range DSLRs might have 20MP sensors or more. And on a computer it's easy to zoom in and pixel-peep... and share your disappointment with everyone else if the lens is bad. For all the legend-making around the Nikon 300mm f2.0, their latest 300mm f2.8 is going to outperform it in every way expect for the number of photons it lets through.
  - pdpi 7y ago
    > even mid-range DSLRs might have 20MP sensors or more. This is actually a funny thing. The APS-C Canon 90D has a slightly higher resolution sensor than the full frame 5Dmk4, and significantly higher than the brand new, also full frame, 1DXmk3. Sony’s APS-C bodies are all 24MP, the same as the a7iii and the flagship a9/a9ii. Other than dedicated high-res models (5DS, a7R, D850/Z7), high-end cameras routinely have much lower pixel density than cheaper cameras, because resolution doesn’t matter that much for most applications, and pros care for a whole bunch of other features that scale poorly with resolution (such as low light performance and buffer drain speed)

ska 7y ago

The focus on f-stops was/is for the same reason people chased high ISO film in the old days, and "ISO" on sensors now, and the focus on extremely long tele's also. This isn't about getting the best image possible but about capturing something you otherwise couldn't get at all. All of this gear is about flexibility to handle poor lighting conditions, things moving quickly, etc. If you are product photographer with a room full of lighting equipment you are going to pick the right lens for the job and make the room work. Other people rarely have this freedom. It's worth noting that in the last couple of generations of digital sensors, we're objectively in a better situation than fast film was, so that loosens the need for fast glass a bit. The same is true for widely deployed mostly ok physical image stabilization systems.

ip26 7y ago
Bird photography is my personal example. If you go back ten or twenty years, you quickly notice much of the bird photos of the age have no background- because high power flash was mandatory. But today, while it is a challenge, it is possible to photograph small subjects handheld in natural light- with the latest & greatest equipment.

farazbabar 7y ago

Some of these lenses are quite amazing. My favorite lens from this class is the leica noctilux at f0.95. It is tac sharp even at f0.95 (if you can nail the focus) and the images make even an amateur like me look like a photo god.