D800 + 85 1.8G focus?

[clive_murray_white]

<p>Hi all - I regularly use my D800 for low light indoor events, ISO 3200 + 85 1.8G takes very nice pictures but......................occasionally it decides, for reasons best known it, that it doesn't want to focus and then won't take the picture. Strangely if I give it a few moments to makeup its mind it works fine. Anyone got any ideas about what's happening or what can be done to make it behave itself properly? Thanks.</p>

[ShunCheung]

<p>A lot of that depends on your AF settings. As starters, what are your custom settings for a1 and a2? Which AF mode are you using, Single, Continuous, how many AF points?</p>

[owen_omeara]

<p>I have that same lens that I use on my d810. I rarely have an issue with my AF but when I do it is just what you described. I am going to follow Shuns advice and see what happens.</p>

<p>-O</p>

[clive_murray_white]

<p>Thanks for the quick reply Shun - I'm a bit old school and set and forget, Single shot + and single point- though I can't seem to see it in the control panel</p>

[clive_murray_white]

<p>Hi again - just looked at AF in the menu and discovered it was set to 51 points the other option was 11, I switched over to 11</p>

[eric_arnold]

<p>i shoot a <em>lot</em> of low-light stuff. unless you're shooting still subjects, i would use AF-C instead of Single focus. that is a much speedier way of shooting events, even in good light. </p>

[elliot1]

<p>For low light photography, using only the center AF points that are cross type will give you the most accurate and most consistent AF.</p>

<p>You may want to leave 51 points active but only use the center 3 columns which are the only ones that are cross type (15 AF points). When you have only 11 points displayed, only 3 of the displayed AF points (the 3 in the center) are the cross type.</p>

[clive_murray_white]

<p>Thanks everyone - I'd better get the manual out!</p>

[clive_murray_white]

<p>Thanks Elliot and Shun, in both of your comments I found myself suspecting that there was something fundamental about focus of the D800 that I'd not grasped..............coming to Nikon from a Leica M8 where none of these intricacies came into play................both my 50 and 85 1.8Gs do the same thing occasionally, so I reasoned that it was an attribute of their cheapness, never happens on 20, 24, 180 or even the 24-85 3.5-4.5 (which is also pretty cheap) but a quick search found a nice explanation of it all from Mr Rockwell, so there's a button in the middle of the AF/M switch! and there I found all of Nikon's ingenious focus variants. And what is more, once set on a less general setting I found it impossible to make the lens decide not to take a picture - so thanks a lot.<br>

Eric - I did try AF-C but didn't enjoy it - but maybe I'll get used to that too.......one day</p>

[ShunCheung]

<blockquote>

<p>so there's a button in the middle of the AF/M switch!</p>

</blockquote>

<p>You are talking about the switch that doesn't really do anything itself. You hold it down to unlock (the settings) and you rotate the main and sub-command dials to control the different AF settings.</p>

[clive_murray_white]

<p>Thanks Shun - I wonder just how many more buttons and rotations of command dials etc lie in wait for me now - thanks again.</p>

[ShunCheung]

<p>Clive, as we discussed recently, reading the entire Nikon owner's manual is not very realistic, unless you really have a lot of time in your hands. However, you have the D800 Quick Guide, right? That is a pretty small booklet and hopefully has the essential basics. In particular, I would go over the Custom Settings (in the Manual Guide section). It helps to be at least aware of which custom options are available.</p><div></div>

[Thomas J.]

<p>Try using your AF Illuminator-assist light in low light situation.</p>

[clive_murray_white]

<p>Thanks Thomas and Shun, interesting re: illuminator-assist and informal photographs of people at events, seeing the light pointing at them could cause problems with their facial expressions.</p>