Btw, I haver now traced the DoF inconsistencies seen in some of my Nex5N shots down to the camera/ambient temperatures. At ambient temps around +30C the camera really starts to produce very strange DoF issues.

I have not found the root of all the focus issues, but I can confirm that depending on conditions if you turn the A77 on it is a very good idea to wait about 2 seconds before assuming it will lock focus before allowing shutter release. That's been the cause of some missed focus also with the new 16-50mm SSM.

I've identified one other likely cause of poor focus at longer focal lengths, AF-S and zooming. The CZ is not a perfectly parfocal zoom, although the focus scale is pretty accurate it is an average and as you zoom the focus will shift. It's not so bad focusing at 80mm then zooming back to 16mm, but if you have composed a shot at something like say 35mm and then zoom to 80mm without removing first pressure from the shutter release the A77 will not refocus and will let you fire the shutter with slightly inaccurate focus. You might never spot it on 6 megapixels (the first camera I used with the CZ!) but on 24 megapixels you do.

Looking at my worst examples, I've often switched the camera on and shot fast (the GPS data absence tells me that) with the lens at 16mm because that's how it is 'parked' in the camera bag. So I've first of all bypassed accurate focus - the lens is still at infinity, the camera has not actually started up fully by the time I've taken half pressure and got 'confirmation'. Then for the next shot I have probably recomposed and zoomed in but never taken my finger off the trigger. Most of my errors are situations where I know I went into overdrive to catch particular things - a fading rainbow, sunshine about to disappear between clouds leaving my 5 seconds to get the shot, a couple of hikers coming down a path and in exactly the right place as long as I shot within half a second - etc.

I think I can safely say that in every case where I had unexpected OOF results, it was a 'grab the camera fast and shoot' situation - and for all the shots where the camera was already switched on, and the image composed as a one off without urgency, things are fine.

One solution to this problem would be to use Eye Start, which I always have turned off, and Continuous AF - which I don't use normally. But I still think that if you turn on and shoot the very instant the viewfinder comes to life (about half a second after switching on) the camera may not be 'ready'.

David

David,

I appreciate the response.

My line of thinking is that if these anomolies are linked to AF-S and/or rushing the start up then it would likley affect other lenses not just the 16-80. So in some way I am relieved to see you also mention the 16-50.
I do usually have my bodies set to AF-C.
If Santa has some space in his sack then maybe he'll have a 16-80 for me.

Thanks for taking the time to explain all this.

Mike

Well, you need to practice the 'quick draw'. My 'reach in the bag and grab the camera' technique is an adjustment of grabbing my pistol for use. On the pistol, I release the safety as I draw it from the holster, on the camera, I turn it on as I draw it from the bag.

This may give you an extra 1/2 second to let the camera get up to speed before shooting.

Dusty

Ok I can visualise it now.
A line up of Sony shooters at a quick draw competition where the object is to get the subject central and in focus in the shortest possible time.
Made me smile.....

Merry Xmas to you and all the Photoworld punters (and David of course without whom we'd all be much less well informed.

Mike

I don't think it's so funny now that there's a shift from cold-sensor to the hot-sensor shooting.

We've seen examples of no start-up warm-up effect with neither the Nex-5, the Nex-C3, a55/33 nor now (maybe) with Nex-7. There definitely are some strange 'effects' with Nex-5N and the a77.

At that, at least the Nex-5 and the Nex-7 show a typical behaviour of a digital sensor without an LPF. The C3 and 55/33 seem to have a way too lax LPF, if any at all, too. And the the 5N and the 77 definitely show the effects of an LPF being present there.

And at the same time, it's exactly the 5N and the 77 that are having some strange DoF/focus issues most likely dependent of the temperature of the sensor.

So far, I'm arriving at some obvious conclusions. But I would love to hear of your very practical experiences. (And I haven't got a Nex-7 to torture yet...)

David, did you check the problem with GPS off?

Well I always thought APS-C was the action format, not the delayed action format. Delayed action flash, and now delayed action general photography too match...good grief, what about birding? what happens if you want to snatch a photo of a bird that's just arrived suddenly and the camera is turned off at that moment?
Greg

Greg - you need an A580 I guess. The EVF cameras, NEX included, all have a significant switch-on delay. I lost pictures from the very first day of using the NEX-5 because of this.

David

Yes David I would most likely be quite happy with an A580 with its extra features, LV, tilting screen and such, over the bodies I have now, but the thing is I would have to get it in from outside OZ as Sony only offers SLT’s here now as far as I can see. And I think Scooterman (maybe) reported there was a flash delay (ala SLT) with the A580 as well, not sure if that is when LV is enabled or not and whether it is not there in normal mode, just not sure on that score.
Greg

Ps I was wrong I can buy an OZ version http://www.myshopping.com.au/PR--357980_Sony_Alpha_A580_Digital_SLR_Camera in OZ its just not stocked by Sony Australia for reasons unknown, well for sure the OZ version is better than getting it in because of the charger wall socket and warranty etc.

With the A580 I've read reports of a flash delay using live view..but it was never clear if it was also present using the OVF. If it was that would cause quite a few problems for me.
Had Sony updated this model with a better viewfinder, and addressed a few areas it would be an easy buy for me right now in fact instant buy! (considering the lenses and A mount equipment I do own)

Barry if I was in the mood for a 16MP camera that comes with a couple of things I don’t like I guess I could buy one of those at the price I can get one for now, an A580 kit for $670 is giving them away. I don’t like where the on/off switch has disappeared to and the OVF is worse than my A100 (which actually I thought wasn’t all that bad), the rear screen sticks out too far by comparison to my current bodies and it has a button on it that I consider to be of no value on a still camera.
I could live with all that (and curse Sony a bit more, but hey, how much is too much), but I couldn’t live with a retard flash, well if it’s only retarded in LV mode maybe there is a glimmer of hope, but I don’t know what the exact position is.
Btw are all you’re a-mount lenses 8 contact jobs?
Greg

& that your Pentax is going back ...


Not too keen on the on/off switch myself but my main gripe is the removal of release/focus priority.
I doubt that you would notice the 0.03x difference & you can always add a magnifying eyepiece.

bfitzgerald wrote Just fitted my HVL-F20AM to my A580 and fired a few flashes. It would appear that OVF setting is instantaneous whereas there is a slight delay when using the LV setting.