alundeb wrote: EB-1 wrote:
That's just ridiculous. Suddenly the Sony 20-600/6.3 seems fast by comparison.
EBH
In the big picture, 600 mm f/6.3 is on the fast side of things.
800 mm f/11 is on the slow side of things, but not exceptionally slow.
Let's take a look at the range of equivalent apertures of some 800 mm options:
#1: 800 mm f5.6 is the fastest option you can get for money and practically use. Either as 400/2.8 +2X, 600 + 1.4 or as 800 mm native. It is extremely expensive and only a very few photographers will ever get to touch one.
#2: 800 mm f/8 is very expensive and rather rare, but more manageable than f/5.6. Only availabale by using teleconverters or sensor areas smaller than 36x24mm. It is avaliable in zooms, but they are then again extremely expensive and very heavy for the aperture.
#3: 800 mm f/9 is only slightly slower than option #2, but the fastest realistic option for most enthusiasts and broadly available even as zooms. It is only 1 1/3 stops slower than the fastest option available.
#4: 800 mm f/11 is the most common option for advanced users not dedicated to very long focal lengths. It can be acheived by using a 2X teleconverter on many popular lenses, but still not considered to be for the masses. The Canon RF 800 mm f/11 DO IS STM is targeting to change that.
#5: 800 mm f/16 equivalent with a 1" sensor (Nikkor 70-300 f/5.6 on Nikon 1 cameras or RX10 IV cropped). This is an extremely size effective 800 mm equivalent option, and believe it or not it is possible to take good pictures with it.
#6: 800 mm f/30 equivalent in the Canon PowerShot SX40 HS. This is considered a slow and poor option. Almost 2 stops slower than the acceptable #5.
Mirrorless on sensor PDAF has made a lot of these options more feasible. DSLRs struggled or flat out didn't support AF at anything slower than f/5.6. Only recently have some of them become useful at f/8. Beyond f/8 Canon won't even attempt AF and Nikon will attempt but it is pretty bad and I stopped using my 500PF/1.7TC on my DSLRs (but that combo is useable on the Z series).
I am curious to see how slow of an aperture the R5/R6 will support for continuous AF. Sony only supports f/11 except for the A9 series that supports f/16.
EDIT: To not risk confusing more people, I am specifically talking about the AF limitations of nominal f/8 lens or lens/TC combos on DSLRs via the OVF (ie not LV) AF systems.
alundeb wrote: EB-1 wrote:
That's just ridiculous. Suddenly the Sony 20-600/6.3 seems fast by comparison.
EBH
In the big picture, 600 mm f/6.3 is on the fast side of things.
800 mm f/11 is on the slow side of things, but not exceptionally slow.
Let's take a look at the range of equivalent apertures of some 800 mm options:
#1: 800 mm f5.6 is the fastest option you can get for money and practically use. Either as 400/2.8 +2X, 600 + 1.4 or as 800 mm native. It is extremely expensive and only a very few photographers will ever get to touch one.
#2: 800 mm f/8 is very expensive and rather rare, but more manageable than f/5.6. Only availabale by using teleconverters or sensor areas smaller than 36x24mm. It is avaliable in zooms, but they are then again extremely expensive and very heavy for the aperture.
#3: 800 mm f/9 is only slightly slower than option #2, but the fastest realistic option for most enthusiasts and broadly available even as zooms. It is only 1 1/3 stops slower than the fastest option available.
#4: 800 mm f/11 is the most common option for advanced users not dedicated to very long focal lengths. It can be acheived by using a 2X teleconverter on many popular lenses, but still not considered to be for the masses. The Canon RF 800 mm f/11 DO IS STM is targeting to change that.
#5: 800 mm f/16 equivalent with a 1" sensor (Nikkor 70-300 f/5.6 on Nikon 1 cameras or RX10 IV cropped). This is an extremely size effective 800 mm equivalent option, and believe it or not it is possible to take good pictures with it.
#6: 800 mm f/30 equivalent in the Canon PowerShot SX40 HS. This is considered a slow and poor option. Almost 2 stops slower than the acceptable #5.
Mirrorless on sensor PDAF has made a lot of these options more feasible. DSLRs struggled or flat out didn't support AF at anything slower than f/5.6. Only recently have some of them become useful at f/8. Beyond f/8 Canon won't even attempt AF and Nikon will attempt but it is pretty bad and I stopped using my 500PF/1.7TC on my DSLRs (but that combo is useable on the Z series).
I am curious to see how slow of an aperture the R5/R6 will support for continuous AF. Sony only supports f/11 except for the A9 series that supports f/16.
Jun 10, 2020 at 07:17 AM
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