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-   -   Help with wide angle lens with out of focus photos (http://www.digitalcameraworld.com/forum/showthread.php?t=7089)

polarmagnus 03-09-11 08:19 PM

Help with wide angle lens with out of focus photos
 
I tried my new wide angle lens this week in the evening.

I have the Sigma 10-20mm lens.

All my photos turned out out of focus/blurred when I viewed them on the computer.

Can I ask how I can make them 'pin' sharp?

markgozz 03-09-11 08:41 PM

Really need to know how you are focusing at the moment and if you are hand held or on a tripod .

But for now try tripod mounted ,f/16 in Aperture priority, ISO 100/200 , and manually focus about 1/3rd of the way into the scene . Also it would be better to use a remote release or self timer to avoid camera shake .
Sorry if I'm telling you how to suck eggs but I don't know your experience .

Mark

polarmagnus 03-09-11 08:46 PM

I was holding the camera.

If its dry tomorrow I'll try f/16 in Aperture Priority and I'll mount it on a tripod. I'll let you know what I can achieve

markgozz 03-09-11 08:52 PM

I think you'll be quite surprised how many tinny little things can cause a blurred image I know I was , you might even want to set the mirror lock as well if you can .

Good luck .

Mark

jet_kit 03-09-11 09:27 PM

Mark's advice is good.
There's a commonly held belief that you don't have to be careful with camera shake/focus with wide angles.
Not so. Whilst it's true to say that the effect is more pronounced the longer the focal length, you still have to watch yourself and continue to obey the rules; Stable platform, tripod, beanbag, or yourself with elbows tucked in, camera properly supported, feet apart, shutter pressed gently, not stabbed etc. etc.
If you're going to have another go tomorrow, try an experiment and arrange a bunch of stuff with good sharp edges on a line leading away from the camera. Select one item about halfway down (not more than 0.5M) to focus on @ f3.5 and check that the focus is not long or short. It is unusual for this to happen, but it's not unknown. It may be necessary to send it back to Sigma for collimation.
Amateur Photographer magazine published a little gadget to check your focus. If you try their website I'm pretty sure it'll still be there somewhere.

MattUK 03-09-11 09:48 PM

I have a similar lens. F11 is the sweet spot. Switch to manual focus, then set the focus ring so the marker is approx .5 cm from the infinity mark. Job done :)

OldBoy 03-09-11 09:53 PM

:D[QUOTE=polarmagnus;61657]I tried my new wide angle lens this week in the evening.

I have the Sigma 10-20mm lens.

All my photos turned out out of focus/blurred when I viewed them on the computer.

Can I ask how I can make them 'pin' sharp?[/QUOTE]

What shutter speed were you using. I normally handhold at 500/s but can go down to 30/s and don't have a problem with blurry images.

polarmagnus 04-09-11 07:46 AM

I should have said that I was trying Manual. I haven't really used the camera in Manual mode since I bought the camera, so maybe this is why I'm finding the photos are blurred. Also I don't really know what I'm doing in Manual. I did however set it to f/22 and changed the aperture accordingly until I thought the photo looked right on the LCD screen. I should look for a course of how to start taking photos in Manual.

I also took a few photos in P mode but they too where a little blurred/out of focus.

I'll try everything on here what people have said to try so far. Yes I have mirror lock-up.

What settings could/should I use in the house?

Jet_Kit
I had to look up 'collimation' on Google to see what it meant. I presume it means something to do with lines??
Could I take a big piece of paper/card and draw a grid, set the camera on a tripod and take a few photos to see if its still blurred?


OldBoy
I knew someone would ask this. I don't know what shutter speed it was, I cannot check now because I deleted my photos off the computer.

silversnapper1 04-09-11 07:54 AM

I think that jetkit may mean calibration.

polarmagnus 04-09-11 10:20 AM

I tried again with different scenery's. I've found out that an f13 or higher is more better than a lower number. And that changing the ISO shows a big change between 100 and 200.

If I want a photo of something close up outside, setting the focus and the AF Point Selection on spot helps.


I have another question. How can I have a different outside the given f-stops other than f4-5.6 what it says on the camera?


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