im using 430 ex speed light with canon eos 20 d

[james_smith36]

Im also using a sigma wide angle lens for low light night club shooting.

time after time i get the same results. great light etc until i get home and find my subjects are blurred horribly and the back ground is crisp

i have heard others with this issue but i cant find an anserw. Please help me figure it out.

the assist beam is what im thinking. the lens works great in studio and the flash works great in normal light situations

just low light. please help

thank you

james<div></div>

[bryantan]

Use single point focus on the subject and you should be fine.

[james_fitzell]

yup, looks like the auto-focus simply chose the background...

 

also, while it's not the case here, any movement of the subject will be very noticeable when you're that close to the camera (although I'm assuming the flash is keeping the shutter speed high enough)

[mark u]

Make sure you are using One Shot focus mode, since there will be no assist beam if you are using AI Servo. Also pick a single AF point: do not use all points mode.

[chrisjb]

Even with flash 1/4 sec is slow to hold still (thats if my exif reader correct) subject or hand hold movements easily throws it out. background is further back so less movement. I`d raise th speed to at least 1/15th, and 800ISO, the 20d is fine at this ISO. Pix always look good on that tiny LCD which is low resolution, how do they look when zoomed right in? I`ve only used center focus point only 20d the left & right point never much good in verticle shots. focus on face FEL and recompose is fine as you are wide at f4 :)

[dave_holland]

One of the problems with the standard setup for the 20D is the fact that your index finger assigns shutter release, exposure, and focus in one step. I find that I have fewer problems with backfocusing when I adjust CF4 to allow focus with the thumb (*). This custom function dissociates exposure and shutter release, giving you the opportunity to adjust each independently. The workflow is to focus with the thumb, recompose, and fire away, with no chance the camera will try to overrule your decision about the correct plane of focus. Try it.

 

Dave

[james_smith36]

I called canon. and they felt that the sigma lens is not communicating properly and were of no help but felt i need ed to

send it in.

The party is tonight so that not possible. Thanks for your help. I will try all your suggestions and ill be here all day if you

have more. If the film is not usable the client does not pay so i need to stop the fear cycle ..LOL

thanks

again.

james

[mark u]

I think Chris JB picked up on a very important point - you really can't expect pin sharp pictures of live subjects (especially hand held) at exposures of 1/4 second even if flash is supplying a good part of the illumination. I'm not sure exactly which lens you are using - the EXIF shows 24mm - so maybe you have f.2.8 to play with to boost ambient exposure along with the ISO.

[johnson_d.]

Sure you can, this is clearly a case of not focusing on the subject.