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A7r, A7r2 - and why I'm keeping both ...

k-hawinkler

Active member
Yep Vivek, a great time saver.
On it I did the error analysis for 60 important historical physics experiments we had to carry out as part of our physics classes. :clap:
 

Pradeep

New member
Ah, nostalgia!

I started with Commodore-64 in '83, did my thesis on it using a word processor I programmed into it from a magazine! From there to the Amiga until they pulled the plug on it.

Then it was the PC from '91 onwards - what a horrible life, used to build my own machines for years and had to rebuild them every 3 yrs or so as they became a 'dog' in performance no matter what I tried.

Finally my son talked me into the Mac world ?8 yrs ago and I've been with it since then.

Nobody can avoid the PC at the work place and it continues to be a nightmare - for me at least. For all its faults, the Mac system is just more appealing to me.
 

Pradeep

New member
K-H, love the shots, the 70-300 seems to be doing a marvelous job, I really like the way it locks on to the eye of the bird. Did you shoot with wide area AF in AF-C mode or did you do a flexible spot?

I wonder if anybody knows how the PDAF algorithm works on the Sony system. I tried to look it up but there is not much information, even the manual does not describe it fully.

What I'd like to do is set up my A-9 (the others are too slow for this) with a wide angle lens, say the 24-70 at 24mm or 35mm and with a remote control (have got that one figured, the Pocket Wizards work really well) to trip the shutter as needed. My intent is to keep the camera in a location where the animals are likely to be active and to catch them as they come closer or as I had mentioned previously, put my camera on an inverted monopod at ground level and shoot from that perspective.

The idea is to get the animal that is closest to the camera in focus, using a wide aperture (low light plus OOF background). I tried using the iPhone smart control, but that does not allow me to pick a focus point on the screen with the A9. With the others (A7Rii and Rx1R2), it does, but I can only shoot one image at a time and the camera then takes a few seconds to write it to the card, will not allow me to shoot until that is done, so won't work. I tried everything but no go. The only way to do this would be to have the camera tethered to a computer via cables, running LR or other tethering software which cannot work in the field for me.

So the only option is to set up the wide angle lens and shoot blind, using the PW to trigger AF and shutter release remotely.

My questions then are:

1. Does the PDAF in AF-C mode with focus area set as 'wide', focus on the object closest to the camera especially towards the center of the frame?
2. Does it focus preferentially on whatever is moving in the field - thus allowing me to focus on the animal instead of the bush.
3. Any possibility of using eye-AF with animals? I know most people claim this does not work.

I tested this by walking around in front of the camera setup as above, using the PW to trigger the system. It does appear that it focuses on the 'bigger' object, i.e. me instead of the flower pots on the ground, and does get it right most of the time. I wonder how it would behave if say two people walked towards the camera but at different distance from it, just off-center. My guess is it would focus on the closer one since it would be seen as bigger and thus the main subject of the image.

Any ideas?
 

k-hawinkler

Active member
A7III rumored to have A9's sensor and AF system - FM Forums

Quote:


"Was at a public presentation by Sony for the A9 on Saturday. There were three main points of focus:


1) the autofocus system and its ability to track to the edge of the frame,
2) silent shutter and the reality of a global shutter in the future, and
3) no blackout and fps speed and the need for fast cards to clear the buffer.


80% of the presentation focused on these three things. Other features like the better battery, dual cards, touchscreen, joystick, sensor resolution, etc, were barely mentioned.

Okay, so, now we know what Sony is focusing on for future products. I would expect all future Sony cameras to concentrate on these three features over everything else."

That seems to sum it up nicely.
Having an A9, I want next an A9r or A9r II with truly silent global shutter.
 
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k-hawinkler

Active member
I am really quite impressed by what the Sony ILCE-9 and Sony FE 70-300mm F4.5-5.6 G OSS are capable of.



Sony ILCE-9 + Sony FE 70-300mm F4.5-5.6 G OSS @ 300mm, ISO 1250, f/6.3, 1/2000s, 3100x3100 crop.

At this early stage of me using the A9 with silent shutter, Center or Lock-on AF: Center seem to work well.
If I use Lock-on AF: Expand Flexible Spot it seems to have some difficulty focusing on a narrow central subject in front of a close-by background. :facesmack:
 
V

Vivek

Guest
Yes, K-H. I see this sort of drop with my A7s. For low light video it is fine.

OTOH, some of the astro modded (cooled) cams are astonishingly very low in noise and with impressive DR. :thumbs:

@ ISO 16,000? :facesmack:
 
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