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RF 600/800mm f/11
#21
(07-14-2020, 10:52 AM)Arthur Macmillan Wrote: This is probably a little off the wall, but take a look again at the diagram for the 800mm f/11:  https://cweb.canon.jp/eos/rf/lineup/rf80...uction.png

Couldn't Canon take the same exact lens, and extend it less by the difference in the focal flange distance between the EF-s  mount and the RF mount and make the same lens available for the Canon 7D Mk-ii/ 70D/ 80D / 90D?  Hopefully they could use an EF/s mount because the imager circle for the APS-C is a lot smaller than for the FF sensor.  Then use it in live view for shots with and angle of view of 800mm x 1.6 or 1280mm?  Yes, I know it isn't going to happen but imagine all that reach!  If it could AF in live view that would interesting to try.  

Would the 7D Mkii would be able to focus and track?  I don't see why we DSLR guys should miss out on everything!

EF-S has the same mount as EF. Only the glass has a smaller image circle. These RF 600mm and 800mm lenses are for FF, so I do not understand why you would want to see it with "EF-S mount".

In live view you can focus with f11.
But DSLRs can't focus f11 when not using live view, the AF sensor won't see anything at f11 (PD AF sensors do not look through the center).
So it makes no sense to make an f11 lens for DSLRs with auto focus, as it will be a nightmare for support depantments of stores, importers and manufacturers would be flooded with questions about why the lens does not focus on the camera (when using OVF).


It would make sense to make such lenses with EF-M mount.
#22
I think Arthur was looking at the reach advantage of APSc for those little birds and critters.
Dave's clichés
#23
(07-15-2020, 06:44 AM)davidmanze Wrote: I think Arthur was looking at the reach advantage of APSc for those little birds and critters.

You can put those lenses on APS-C with EF mount.
#24
"I think Arthur was looking at the reach advantage of APSc for those little birds and critters. "

Correct Dave! I can remember back the the big splash the was made when the 70D came out with it's dual pixel focusing. The thing that grabbed me was the claim that the camera could focus in very little light. A reviewer claimed that in live view the 70D could focus in almost total darkness! So I wanted to see if the 70D could "Focus in the dark". I ended up buying one, and what I remember is that it really could focus in very low light. The point being I was not really surprised that both of these new lenses can AF even with a 2x tele on them.

So what I was thinking was what kind of result you could get with an APS-C sensor. I know you could adapt the FFD by using less extension. At any rate I just bought the 90D recently.

...yes I know the bayonet mount part of the EF and EF-S are the same, and either one would work. My idle question was that maybe the lens might not have to be majorly redesigned if used on, let's say a 90D in Live View Mode. At least as far as image circle and enough room for the lens to fit on the camera. So I am imagining 800mm x 1.4 tele x 1.6 crop and thinking 1,792mm could be realized. A birders dream!

The M Mount cameras are just too small...Which has been my complaint all along. I want a form factor that fits large hands, and an APS-C sensor...And these new lenses!

I really can't afford an RF camera, so I this is just clouds in my coffee!
#25
What is FFD?

The lens optics would work just fine on EF, so also on a 90D. The electronics are RF, and would have to be redesigned to work with EF, and of course the lens would have to be shortened a bit (flange distance) and have an EF mount to make sense on EF cameras like the 90D.
#26
Sorry BC, I can go overboard with the abbreviations, and it wasn't even necessary. People use different terms, but I meant Flange to Focal plane Distance. Normally you can't adapt a mirrorless lens to a DSLR because to have the same FFD there would not be room for the rearmost elements. The F/11 lenses (from the drawing you linked to earlier) don't seem to have glass in them. I am pretty sure I've never seen a rangefinder, or mirrorless lens that could be made significantly shorter just by shortening the end of the lens.

FFD's concerned are EF is 44mm, RF is 20mm so the RF F/11 lens would have to shortened (extended less) by 24mm. Amazingly this is not optically a big issue. Of course Canon would have to provide the EF mount, and shorten the tube.

And who knows if it would even work. Possibly shortening the tube would shorten be focal length at least a little. But if it worked, I might finally get closes enough to the very high nests of some of the Herons, and Hawks that nest very high up in trees, or get photos of birds on rocks that are a ways away from the cliffs on the shore near where I live. I could endure Live View to get to do that!
#27
(07-16-2020, 07:10 AM)Arthur Macmillan Wrote: "I think Arthur was looking at the reach advantage of APSc for those little birds and critters. "

Correct Dave!  I can remember back the the big splash the was made when the 70D came out with it's dual pixel focusing.  The thing that grabbed me was the claim that the camera could focus in very little light.  A reviewer claimed that in live view the 70D could focus in almost total darkness!   So I wanted to see if the 70D could "Focus in the dark".  I ended up buying one, and what I remember is that it really could focus in very low light.  The point being I was not really surprised that both of these new lenses can AF even with a 2x tele on them.

So what I was thinking was what kind of result you could get with an APS-C sensor.  I know you could adapt the FFD by using less extension.  At any rate I just bought the 90D recently.

...yes I know the bayonet mount part of the EF and EF-S are the same, and either one would work.  My idle question was that maybe the lens might not have to be majorly redesigned if used on, let's say a 90D in Live View Mode.  At least as far as image circle and enough room for the lens to fit on the camera.  So I am imagining 800mm x 1.4 tele x 1.6 crop  and thinking 1,792mm could be realized.  A birders dream!

The M Mount cameras are just too small...Which has been my complaint all along.  I want a form factor that fits large hands, and an APS-C sensor...And these new lenses!

I really can't afford an RF camera, so I this is just clouds in my coffee!

 Hi Arthur,
               Ah, dreams !!....
I see your logic and I think we have all dreamed about such combinations to get that frame filling shot .... 
...... I've tried the AF-S 500mm/600mm F4 + a 1.4X converter on both FF and the APSC sensors (1.5X crop)...... all readily available gear.
   I haven't the most recent converter being the older Nikon TC14E II, the MkIII version being said to be a little better ...... however, I found that sharpness tends to hold up only when you are close .... which is great for small birds . ..... 
 ....... as soon as you are any real distance things get soft again often with lower contrast/veiling and results tend to look a little like from a super-zoom bridge camera. .... if your used to sharp results you just won't be happy.
    ........ the magnification of air disturbance plus the tele-converter takes the hit ...... cropping is better and of course cheaper!

 Unfortunately, getting close enough is the bain of bird photography!
Dave's clichés
#28
Hi Dave-

Right again! I live less than a mile from the ocean. Sometimes you do get a break an the thermal heat waves if you are shooting across the water, since the water doesn't heat up the way the ground does. But in general, yes, at shorter distances a teleconverter seems to work better than long distances. I'd just like to see what the 800 could do with a 1.4x, or a 2x.

There have been a few sightings of unusual birds here where that combination would be great if it worked well. For my purposes the 90D with the 100-400ii + Tamron SP 1.4x tele has proven to be a lot of fun. Maybe a Sigron 150-600mm would be better for distance shots...but I do love the easy handling of the smaller lens! You know how it is in the back of my mind the question is what next? I will be eyeing these new lenses.

I know there is a lot of pent up demand for lenses like this, if the performance is good.
#29
(07-19-2020, 08:28 PM)Arthur Macmillan Wrote: Hi Dave-

Right again!  I live less than a mile from the ocean.  Sometimes you do get a break an the thermal heat waves if you are shooting across the water, since the water doesn't heat up the way the ground does.  But in general, yes, at shorter distances a teleconverter seems to work better than long distances.  I'd just like to see what the 800 could do with a 1.4x, or a 2x.  

There have been a few sightings of unusual birds here where that combination would be great if it worked well.  For my purposes the 90D with the 100-400ii + Tamron SP 1.4x tele has proven to be a lot of fun.  Maybe a Sigron 150-600mm would be better for distance shots...but I do love the easy handling of the smaller lens!  You know how it is in the back of my mind the question is what next?  I will be eyeing these new lenses.

I know there is a lot of pent up demand for lenses like this, if the performance is good.

 I think the maxim of:  "try before buy" would be in order here!
Dave's clichés
#30
Yes, Dave, I would have to try before I buy!


As an aside, I believe that the 20MP (full frame) camera is not diffraction limited until about f/13, so for that camera, if I am right, it would not be absurd to expect sharpness. And I was serious that the aperture stopping down can effect sharpness.

Now about my fantasy...I have used the 70D, and you have been using the D500, both of which are APS-C, though I had to deal with a tougher 1.6x versus your 1.5x. I used my 70D for Macro quite a bit at f/11 and didn't seem any the worse for it. I know in theory there should be diffraction, but since it was often necessary for a sufficient DOF I had to use it. Therefore I am not expecting it to be unusable with a telephoto.

Still, I would, in reality, want to go back to 20mp. I can always do some shooting at f/11 with the 90D, but now that I think of it...I have been mostly shooting wide open. If you can call F/5.6 wide, that is!

The truth that is sinking in, is that I am hooked. I think I might actually want an RF camera! Maybe not now. But soon!

-Mac
  


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