p.2 #1 · Rokinon 16mm f/2 lens available for pre-order
1slowg35 wrote:
The focal length is the only thing that changes (24mm 1.5x crop factor), the aperture doesn't change for a cropped sensor. It'll still be a f/2
You get f2 light but you get 2.5 DoF, IIRC. If I'm wrong that's fine, not trying to start another debate, just clarifying what the person you quoted was joking about.
Personally this sounds very interesting. Will have to see how it compares to the Sony 2.8. I wish samyang would get their build quality up though. Plastic screws into plastic holes? Really?
p.2 #3 · Rokinon 16mm f/2 lens available for pre-order
Pretty close to the 14 2.8; my only problem with that amazing lens was how long the focusing throw was on my NEX7. Hopefully this one will be shorter...
@1slowg35: "..The focal length is the only thing that changes (24mm 1.5x crop factor), the aperture doesn't change for a cropped sensor. It'll still be a f/2.."
The aperture does not change in terms of exposure, but does in terms of bokeh behaviour.
May 30, 2013 at 08:50 AM
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p.2 #4 · Rokinon 16mm f/2 lens available for pre-order
Well, not everybody aims for as shallow a DOF as possible all the time.
p.2 #5 · Rokinon 16mm f/2 lens available for pre-order
1slowg35 wrote:
The focal length is the only thing that changes (24mm 1.5x crop factor), the aperture doesn't change for a cropped sensor. It'll still be a f/2
Neither the focal length nor the f stop change. Both are physical properties of the lens. Only way to change either is to use optics, such as a teleconverter or telecompressor (the latter is a Speed Booster or Lens Turbo)
The Field of view of 16mm on APS-C is that of a ~25mm lens on 35mm FF. The DoF is equivalent to a 25mm f3.2 lens (this is not an FF/APS-C equivalency but rather a 25mm f3.2 lens has the same DoF as a 16mm f2 lens on the same format), as is the total illumination (and thus the SNR equivalence).
p.2 #6 · Rokinon 16mm f/2 lens available for pre-order
Snopchenko wrote:
I can practically hear the choir of those who would be saying "Why don't you just get a FF camera, because this lens is equal to 25mm f/3.2!" or something.
p.2 #8 · Rokinon 16mm f/2 lens available for pre-order
Cgb628 wrote:
Oh dear. It appears to be a short flange distance. There go the hopes of a good 24mm equivalent on APS-C DSLRs.
The problem, as I understand it, is that APS-C DSLRs have inherited the same register distance as their FF big brothers, instead of a register distance optimized for the sensor size. As as result the complexity of making a 16mm f2 APS-C DSLR lens will be closer to complexity of a FF 16mm f2 lens, rather than a FF 24mm f2 lens. So we are not likely to get a lens like that.
p.2 #9 · Rokinon 16mm f/2 lens available for pre-order
curious80 wrote:
The problem, as I understand it, is that APS-C DSLRs have inherited the same register distance as their FF big brothers, instead of a register distance optimized for the sensor size. As as result the complexity of making a 16mm f2 APS-C DSLR lens will be closer to complexity of a FF 16mm f2 lens, rather than a FF 24mm f2 lens. So we are not likely to get a lens like that.
It would be actually pretty impractical to reduce the register much for a native APS-C DSLR mount. 4/3rds mount, which did not inherit any legacy mount issues, has a register of approximately 38mm, a bare 2mm shorter than Konica AR mount, the shortest register of reasonably common FF mounts. It's unlikely that a decent APS-C native mount would be much shorter than the 44-46.5mm of the current 35mm AF mounts.
p.2 #11 · Rokinon 16mm f/2 lens available for pre-order
mawz wrote:
It would be actually pretty impractical to reduce the register much for a native APS-C DSLR mount. 4/3rds mount, which did not inherit any legacy mount issues, has a register of approximately 38mm, a bare 2mm shorter than Konica AR mount, the shortest register of reasonably common FF mounts. It's unlikely that a decent APS-C native mount would be much shorter than the 44-46.5mm of the current 35mm AF mounts.
I believe 4/3rd register distance was relatively large for the format because of the strict telecentricity requirements introduced in the 4/3rd standard. Otherwise it could have been shorter.
A simple way to see the impact of "improper register distance" is in the design of normal lenses for APS-C DSLRs. For example Sony 35mm 1.8 lens for APS-C is larger than Sony 50mm 1.4 lens for FF. This is because despite being a "normal" lens for the APS-C format, it has to be designed as a wide-angle lens due to the larger register distance. I am fairly sure that if an APS-C only DSLR mount is created then it will make it much easier to create fast wide-to-normal APS-C lenses.
p.2 #14 · Rokinon 16mm f/2 lens available for pre-order
I like what this company is doing, but I wish they made a version specific to mirrorless. I mean, come on, 77mm filter thread for mirrorless? This lens will probably look out of place on my NEX-7.
