picture slightly out of focus

[Menno]

Hi,

This is my first post on Helifreak but I see a lot of familiar names here from RR.

I would like your opinion on this picture. It seems that whenever I take a picture with the focus set to infinity, the focus is slightly of. When I take a picture with the subject in close range this problem does not seem to occur.

http://home.xmsnet.nl/vonk/emiclaer_S.jpg
shutter 1/250|iso 400|F4

A larger version can be downloaded from here (1,4 Mb): http://home.xmsnet.nl/vonk/emiclaer.jpg

Picture was taken well after 9 PM, so lighting was beginning to be a problem.

Also, how high do you think I was. I could see the heli just fine, but it was difficult to see the direction of the tail.

Menno

[slow]

Knowing what camera / lens you're using would help..

I'm guessing it's a DSLR though. If so, the "cheaper" lenses (non-pro) sometimes overdrive the focus, meaning that turning the focus ring all the way to infinity is actually _more than_ infinity. Try nudging the focus back a few millimeters.

Oh, and to clear up your images and get better color in them, try out a polarising filter.

/James

[Menno]

Hi James,

Yes it's a DSLR, the Canon 350/Rebel XT with the stock 18-55 lens. This picture was taken at 20mm.
I'am going to upgrade to another lens soon, but I have not decided on which yet. For under the helicopter the 20mm 2,8 prime from Canon really looks good. For my pole I would rather buy the Sigma 10-20mm. So many lenses, so little budget :dontknow .

Menno

[slow]

Yep, with that lense, I'd definitly try to nudge back a bit on the focus ring. You can usually test out how much you need to turn it while still on the ground by trying to focus on something very far away. If you cant see it by eye, snap a picture and zoom into it on the camera.

As far as lenses go for AP, I'm not the right man to ask. I don't do AP, but I'm a fairly active ground-based photographer.
My favourite lense is the Canon 50mm F/1.4.. But that's probably _way_ too narrow for you to use on an AP setup.

/James

[Menno]

I was hoping somebody would take a guess at the hight of the picture also :fly .

Anybody?

Menno

[slow]

Guestimate: 150meters (500ft for you yanks)

/James

[Nitrospazzz]

Sorry to jump in here with another question but I am using the same camera and have a question. When you talk about nudging the focus back a little bit. Are you guys using manual focus? I was planning on using auto focus but if blurry pictures are the result I will have to experiment.

I haven't taken any photos yet but plan to start taking as many as possible this week once I get my mount issue figured out

[slow]

Well, there really is no point in using autofocus, as I'm guessing you wont be photographics something closer than about 20ft away. So, you already know what the focus setting will be: "Infinity"

Autofocus also has the drawback that it takes the camera about 0.2->0.4 seconds longer (depending on your lens) for it to take a picture, as it has to evalute and try to set the focus before it takes the picture.
Another drawback is also that if your focuspoint is pointing towards a blue sky or a white cloud (no sharp contrast), it can take the camera several seconds to take the picture as it will have trouble finding the focus, and in the absolute worst case, it cant find the focus at all, and simply wont take the picture..

/James

[SeaHawk]

Menno,
I've been using the Rebel 350 for couple of seasons now. I use auto focus with great sucess. Set it to auto and it will work. Also use the jomar shutter release with it.