D800E supremely able autofocusing

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I thought I post something positive about D800E AF.

I just shot about 200 photos in some caves, often very dark and the AF worked almost every time. I was amazed. 24-70 F2.8ED. It was extremely fast and accurate and AF just got out of the way for the photo.

Fantastic performance.

Greg.
 
Astrophotographer 10 wrote:

I thought I post something positive about D800E AF.

I just shot about 200 photos in some caves, often very dark and the AF worked almost every time. I was amazed. 24-70 F2.8ED. It was extremely fast and accurate and AF just got out of the way for the photo.

Fantastic performance.

Greg.
Greg, just to double check, you were shooting at f/2.8 aperture, right? Was it in AF-S or AF-C mode? Any AF assist light?


Leo
 
Astrophotographer 10 wrote:

I thought I post something positive about D800E AF.

I just shot about 200 photos in some caves, often very dark and the AF worked almost every time. I was amazed. 24-70 F2.8ED. It was extremely fast and accurate and AF just got out of the way for the photo.

Fantastic performance.

Greg.
I like the images you attached to your post. They look gorgeous and definitely proof how great the AF is under low light conditions.
 
gl2k wrote:
Astrophotographer 10 wrote:

I thought I post something positive about D800E AF.

I just shot about 200 photos in some caves, often very dark and the AF worked almost every time. I was amazed. 24-70 F2.8ED. It was extremely fast and accurate and AF just got out of the way for the photo.

Fantastic performance.

Greg.
I like the images you attached to your post. They look gorgeous and definitely proof how great the AF is under low light conditions.
I also enjoyed the images especially when viewed with the eyes closed.

Leo
 
Please post some of your images. I believe your statement but would love to see the pictures.

I love my D800 but can't seem to get my images quite as sharp as others. Sometimes they are, which makes me think the fault is mine. Regardless, I tend to think Nikon was just not quite ready to release such a high megapixel sensor. There's no question that it magnifies any flaws in personal technique, lens, lens-D800 combo, etc. When it's on, however, it's awesome. Still the best camera I've ever owned (last was D300).
 
Leo wrote:
Astrophotographer 10 wrote:

(snip) some caves, often very dark and the AF worked almost every time.
you were shooting at f/2.8 aperture, right?
Not sure what you're trying to check. Just to make sure you'are aware of the following: Af is always performed with the lens wide open. The diaphragm closes to the selected aperture only once the shutter is full pressed.
 
I went into some old gold mine with a friend who had a Canon 5DII and I had the D7000 then with a SB900 flash with the Asssist Lamp on. The miner told us there was an ore cart ahead of us in the dark. I pointed the camera and flash at the area and saw the assist lamp red bars, but no shot. When the miner turned on his LED flashlight, the camera got a lock and fired off this shot.







Granted it was pitch black in there, but it did a good job considering the darkness. The flash assist wasn't able to get a reading to unlock the shutter without the miner's light though. The Canon couldn't fire at all so I don't know what was up with that so he did some light painting on Bulb with it sitting on a rock.


Mack
 
Thanks for the compliment but those night sky shots are all manually focused. To be honest I probably one tried AF once and assumed it would not be reliable. Those shots are at a dark site and its REALLY dark. The nearest light pollution is over 100kms away and there are small mountains in between them and me.

Greg.
 
Certainly. Give me a day or so to download them all and process them. I took lots.

I think your remark is a fair comment. I'd agree with that. In camera stabilisation like OMD EM5 would be very nice on this camera. I am more inclined to get VR lenses for this camera. It does put pressure on you to keep the camera still whilst shooting and also to use as high a shutter speed as you can for the smallest ISO you can. ISO6400 though is useable with a bit of noise work.

I also used the HDR function a lot in one of the caves. One cave I mostly had it set to HDR,TIFF and series and in the other cave I turned it off and used RAW only. The camera has so many choices.

Greg.
 
I rechecked the camera as I haven't changed anything to see if the AF assist light was on. Yes the menu has the AF assist illuminator turned on. I don't recall seeing it though. Except in one or two shots where it was too dark and the underexposed image was very red. A lot of the scenes where AF worked were far away and it still locked very quickly. In fact so quickly that I took several 6 to 8 image panoramas very quickly.

Greg.
 
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TOF guy wrote:
Leo wrote:
Astrophotographer 10 wrote:

(snip) some caves, often very dark and the AF worked almost every time.
you were shooting at f/2.8 aperture, right?
Not sure what you're trying to check. Just to make sure you'are aware of the following: Af is always performed with the lens wide open. The diaphragm closes to the selected aperture only once the shutter is full pressed.
 
Leo360 wrote:
TOF guy wrote:
Leo wrote:
Astrophotographer 10 wrote:

(snip) some caves, often very dark and the AF worked almost every time.
you were shooting at f/2.8 aperture, right?
Not sure what you're trying to check. Just to make sure you'are aware of the following: Af is always performed with the lens wide open. The diaphragm closes to the selected aperture only once the shutter is full pressed.
 
Last edited:
Astrophotographer 10 wrote:

I thought I post something positive about D800E AF.

I just shot about 200 photos in some caves, often very dark and the AF worked almost every time. I was amazed. 24-70 F2.8ED. It was extremely fast and accurate and AF just got out of the way for the photo.

Fantastic performance.

Greg.
shooting in near dark for both static and moving subjects - the focus lock was consistent and reliable including in extreme af points for older screw driver lens (like 80-200mm @200mm)
 
No and No. As Marianne found out through experimentation, D800 AF uses f/5.6 effective aperture for most of the lenses and f/8 for the ones that cannot do f/5.6. Even if your lens is 50mm f/1.8 the AF sensors only observe f/5.6 area of the lens. Another reason to know what aperture was used is to see how much deep DOF obfuscated focusing errors.

Leo
Quite interesting findings. But how can the AF sensor ONLY uses f/5.6 effective aperture when the lens is mechanically opened to full aperture?
 
Leo360 wrote:
TOF guy wrote:
Leo wrote:
Astrophotographer 10 wrote:

(snip) some caves, often very dark and the AF worked almost every time.
you were shooting at f/2.8 aperture, right?
Not sure what you're trying to check. Just to make sure you'are aware of the following: Af is always performed with the lens wide open. The diaphragm closes to the selected aperture only once the shutter is full pressed.
 
Last edited:
I absolutely agree with this. D800 focus is awesome, especially in low light.



 

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TOF guy wrote:
Leo360 wrote:
TOF guy wrote:
Leo wrote:
Astrophotographer 10 wrote:

(snip) some caves, often very dark and the AF worked almost every time.
you were shooting at f/2.8 aperture, right?
Not sure what you're trying to check. Just to make sure you'are aware of the following: Af is always performed with the lens wide open. The diaphragm closes to the selected aperture only once the shutter is full pressed.
 
Leo360 wrote:
TOF guy wrote:
Leo360 wrote:
TOF guy wrote:
Leo wrote:
Astrophotographer 10 wrote:

(snip) some caves, often very dark and the AF worked almost every time.
you were shooting at f/2.8 aperture, right?
Directly from the Marianne's mouth

http://forums.dpreview.com/forums/post/50092107


"Conclusion

Testing has demonstrated that AF is incapable of using any light rays passing through the lens, peripheral to the center f/5 aperture.
"

Leo
Correct. But it is also true that the aperture stays open until the shutter is actuated. (Otherwise you would lose viewfinder brightness.)
 
Leo360 wrote:
TOF guy wrote:
Leo360 wrote:
TOF guy wrote:
Leo wrote:
Astrophotographer 10 wrote:

(snip) some caves, often very dark and the AF worked almost every time.
you were shooting at f/2.8 aperture, right?
Not sure what you're trying to check. Just to make sure you'are aware of the following: Af is always performed with the lens wide open. The diaphragm closes to the selected aperture only once the shutter is full pressed.
 

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