p.8 #1 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
May I ask ilkka_nissila?
Ilkka - do you think the problem some folks are having is just a limitation of the camera and lens (most likely the camera) - the A7R4? Are we expecting too much from the camera?
And please remind me, what test(s) would you recommend we do to determine if there is indeed a problem in getting consistent, accurate focus with the 200-600 and the A7R4?
p.8 #2 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
EstherSP wrote:
Many people simply don't "need' a blackout free shutter, or IBiS, or 20 fps. A blackout free shutter wouldn't help with the OP's issue for example.
Maybe you don't feel the "need" for those features personally, but having those capabilities does put the a9 ahead technology wise. A distinction you seem unable to recognise.
p.8 #3 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
rdcny wrote:
I wonder what sort of controlled test we could do to isolate (or narrow-down) the problem?
As I have been suggesting, because the Sony focusing system is so much more sensitive to vertical contrast, try to create a situation where the problem exists in landscape mode, then switch to portrait mode without changing anything else to see if that helps.
p.8 #4 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
(I've had the most problems when horizontal lines - waves for example - are part of the image...That has been the biggest problem area so far with my use of the A7R4 and the A9)
p.8 #5 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
1bwana1 wrote:
Maybe you don't feel the "need" for those features personally, but having those capabilities does put the a9 ahead technology wise. A distinction you seem unable to recognise.
We are speaking specifically to your comment regarding the AF being miles ahead. Which you seemed to walk back a little after being called out by people in this thread that have actually shot the referenced cameras. Anyways, I'll drop it as this thread already has enough weird passive aggressive comments and bickering.
p.8 #9 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
rdcny wrote:
(I've had the most problems when horizontal lines - waves for example - are part of the image...That has been the biggest problem area so far with my use of the A7R4 and the A9)
Interestingly, according to Galer the AF is more sensitive to vertical lines. I'm still looking for a "white paper" which chronicles the function of each setting. For example does "sensitivity" affect target acquisition speed, responsiveness, etc. or just "stickiness"?
p.8 #10 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
Yes like Canon the Sony "in camera" description of each setting is murky at best. If I remember correctly, at one point Canon came up with longer descriptions of what each setting did - white papers as you mention.
p.8 #11 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
I spent the evening re-watching Galer's hour long video on the Sony AF system, hoping to uncover some unseen nuggets of wisdom. Unfortunately, there weren't any and while I respect him for all of the good work he does, I'm coming to the conclusion that Galer doesn't have or isn't willing to share the detailed technical information (I think it's probably the former). We need a "white paper" describing in detail the function of the AF system and how the various settings and permutations influence AF.
Parenthetically, I read an offhand comment by Art Morris about his recent experience with the 200-600 on his A9II and how he was surprised that it was repeatedly missing AF. Though he was attributing this to operator error, he has extensive experience with these bodies and shoots with the 600mm f/4 amongst a variety of lenses.
Today, I am no closer to discovering why the quixotic combination of the a7RIV and 200-600 is less than reliable. Is it attributable to some issues with the handoff between PDAF and CDAF, limitations in sensor read rate, lens AF speed (doubtful), IBIS/OSS conflicts, lens/body interface... or something else? Is it potentially addressable through firmware or are the observations simply manifestations of the limitations of the technology?
p.8 #12 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
You might send your comments to Artie and point him to this discussion...I remember when Artie was a public school teacher in Brooklyn (late 1980s) and spent weekends and free time at Jamaica Bay (Queens) doing shorebird counts and shorebird photography...Back then Artie taught in a "rough" neighborhood - though a lot of NYC was rougher then than now ("Lou Reed NYC"). Anyway, Artie could always talk - got him through many tough times.
p.8 #13 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
armd wrote:
Parenthetically, I read an offhand comment by Art Morris about his recent experience with the 200-600 on his A9II and how he was surprised that it was repeatedly missing AF. Though he was attributing this to operator error, he has extensive experience with these bodies and shoots with the 600mm f/4 amongst a variety of lenses.
Having shot side by side with Art twice in the last few weeks, and discussing this very issue I can say that he is not a fan of the 200-600 on the a7RIV. I saw him shoot a number of the Sony long lenses. I don't recall that he never brought out the 200-600. Not even sure whether he brought it on the trip with him.
p.8 #14 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
1bwana1 wrote:
Having shot side by side with Art twice in the last few weeks, and discussing this very issue I can say that he is not a fan of the 200-600 especially on the a7RIV. I saw him shoot a number of the Sony long lenses. he never once brought out the 200-600. Not even sure whether he brought it on the trip with him.
p.8 #15 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
Rishi Sanyal PhD who is the technical editor/equipmet reviewer at DP Review sent some comments:
Hi Bob,
"Yes, there are many intricacies to the OSPDAF, and I've tried to tease these out talking to engineers in Japan. Unfortunately, either due to confidentiality reasons or things lost in translation, I've never gotten definitive answers to questions as simple as:
'Does your OSPDAF system need any calibration per lens (essentially, microadjustment)?'
"People of course say that since AF is being performed on the sensor itself, there shouldn't be any need for microadjustment. But I don't believe it to be so simple. One of the major reasons for microadjustment in DSLR PDAF systems was separate from the fact that the distance to the secondary module might differ from the optical distance to the sensor. DSLR PDAF systems look at 'left-looking' and 'right-looking' light rays through virtual apertures that only look at light entering the peripheries of the lens, which means that lenses with significant spherical aberration need corrections to the PDAF reading to account for the fact that image forming light is made up of both peripheral and central (on-axis) light rays.
"My theory is that with half-masked pixels (or Canon's dual pixel AF), this shouldn't be an issue, since the AF sensors are sampling full 'half-cones' behind the lens aperture. But if a company happens to use a different masking geometry (say, quarter masks), the OSPDAF measurements would need correction based on the spherical aberration properties of the lens."
p.8 #16 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
That’s fair though why would the same lens work fine on an a9 and the fail on the a7riv? It points more to the camera body rather than need for SA correction. My personal belief is it has something to do with the Camera settings, read rate, pdaf/craft, or ibis/os. In any event, it’s not a reliable lens on the a7riv.
p.8 #17 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
This issue has now received a wide airing here on FM and appears conclusive to me. I presume members of this forum are not alone in recognising it. In my opinion it has now achieved a similar status to Nikon's oil on sensor problem a few years ago and, more recently, focusing issues on Canon's new RF 70-200/2.8. Both companies addressed the problems (although I recall Nikon was very slow to react or even admit a problem). I think it is now incumbent on Sony to sort this out PDQ or they may well find themselves facing a deluge of returns.
p.8 #18 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
waterden wrote:
This issue has now received a wide airing here on FM and appears conclusive to me. I presume members of this forum are not alone in recognising it. In my opinion it has now achieved a similar status to Nikon's oil on sensor problem a few years ago and, more recently, focusing issues on Canon's new RF 70-200/2.8. Both companies addressed the problems (although I recall Nikon was very slow to react or even admit a problem). I think it is now incumbent on Sony to sort this out PDQ or they may well find themselves facing a deluge of returns....Show more →
p.8 #20 · Brief Comments on the 200-600 with A7R4 (Harlequin Duck)
waterden wrote:
The lens, of course! It should be able to focus properly on all modern Sony A bodies, not just the A9 series. The A7Riv is fine with every other lens.
I don't know. My 200-600 worked great with the A7RIII for airshows, nice and sharp. Of course AF for airshows is not really that demanding. I used the A7RIV and the 200-600, and sometimes with the 1.4 TC a couple times to shoot bald eagles. I did get some sharp shots, even at 840mm. My keeper rate is probably 3-4 out of 10, depending on the situation. I haven't had opportunities to test more on BIF. I got some pretty sharp shots of backyard birds through a double pane glass patio door too but these birds weren't really moving much.
I really hope Sony will make A9 type of APSC body for sports/wildlife. I had my hope high for a while last year...
