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'Reculver' - soft focus with Tokina lens or weather issue?

Posted: Wed Jun 22, 2011 1:57 pm
by DrScottNicol
So after being inspired by the UWA thread a few weeks ago, I decided to upgrade my tamron 10-24 to the much better reviewed Tokina 11-16. Now, before I purchased I trawled the net looking at reviews on various bodies and knew this was a lens thats a bit quirky BUT was generally regarded to be very sharp, even wide open at f2.8. So I was a bit disappointed with my first days shooting - many of the shots were just a bit soft whenever I focussed at a distance. The shot below is an example.

a55 body, 1/40th Sec, 11mm, f4, iso 100

Image

link to larger image below

https://picasaweb.google.com/Dr.Scott.N ... 0793742994

Note that the wall in the centre is reasonably sharp (about 5 metres away) but the towers (about 40-50 metres away) just look a little soft to me. The wall to the left is blurry BUT that was very close to the lens so I'm less worried about that. I was using autofocus (single shot mode) and was definitely targeting the towers (I think I was aiming for between the 3 windows), not the wall in the foreground. So my initial response was one of disappointment when I saw quite a few of these type shots. By my calculations, at these given settings using this UWA, my depth of field should have been huge and pretty sharp across the frame.

However, it then occurred to me WHY I was so close to the wall - it had started to rain a little - not a lot but enough for me to want to shelter the front of the lens behind the wall whilst I took the shot. As noobish as this sounds, this is probably the first time I've been out shooting in the rain (as opposed to just after it stopped) so I was wondering if this might explain why my shot was a lot softer than I expected? I'm pretty sure the lens filter was clean / rain free as I checked just before the shot was taken and if was only just raining so by eye it looked pretty clear / high contrast, but I guess the lens sees things slightly differently through all those small droplets? Apart from the obvious (don't shoot in the rain :-)) how do people here normally deal with these sorts of conditions?

I've since taken some more test shots on a sunny evening in Bath and whilst I haven't processed them yet for uploading, they look a lot sharper on my ipad screen so I don't THINK the Tokina has focussing issues but as its new, now's the time to spot them and return it for minimal hassle if it does.

Regards
Scott

Re: 'Reculver' - soft focus with Tokina lens or weather issu

Posted: Wed Jun 22, 2011 6:17 pm
by Dusty
Doc, Looking at the larger pic on the web, I'd say you caught the focus on the wall right in front of you. It looks progressively more OOF as you go back from that.

Dusty

Re: 'Reculver' - soft focus with Tokina lens or weather issu

Posted: Sat Jul 28, 2012 10:31 pm
by gio67
Scott, I find with this lens that autofocus tends to not do so well,ie all over the place, maybe this is a problem with uw lenses, I generally always manual focus and no problems, I'm using the a580