50mm 1.4 acting up

I was shooting some news the other day, and I noticed something wonky going on with my 50mm 1.4. When the aperture is anywhere from 1.4 to 2.8, there is no focus, and the white balance becomes a gradient, with the bottom of the frame being more warm.

Example - taken with the 50mm at f1.4, 1/3200:

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

Indoor fluorescent lighting will cause color shifts like that. Are you sure that is not the problem?

Try some at 1/60 or slower to eliminate that concern.

As for the focus problem, I don't know.......

Mike,

Thanks for the tip on the white balance. I think I knew that subconsciously, but never put two and two together. That did make a huge difference.

The focus is still completely off, though. In Aperture priority mode, I set it to f1.4 and focused on the same point. The result is completely unacceptable, like I didn't focus at all.

I know some people have had trouble with the AF motor dying, but it won't focus correctly even in manual focus. Everything looks great through the viewfinder, but it looks like crap on the sensor.

What distance are you shooting at?

I'm shooting from about six feet, plenty of space to satisfy the minimum focusing distance of the 50mm.

Even on the tripod with a timed shutter, there is no focus.

Maybe it's time to find another body to try it on.

It should also be noted that I let photobucket resize the pics to 800x532. I realize now that was a mistake, because their resizing mechanism is crap, and it makes even the focused parts of the pics look unfocused. In the 17-85mm test shot, the list showed up perfectly readable before photobucket mangled the pic.

msowsun wrote in post #9296120
Indoor fluorescent lighting will cause color shifts like that. Are you sure that is not the problem?

Under/over exposure can also cause apparent colour shifts. If my quick mental math is correct f/1.4 @ 1/3200 is not the same as f/5.6 @ 1/250 (slightly overexposed). However, if it is slightly overexposed, one would think it would not be so dark in comparison to the other two...

Sonic Infidel wrote in post #9296151
The focus is still completely off, though. In Aperture priority mode, I set it to f1.4 and focused on the same point. The result is completely unacceptable, like I didn't focus at all.

I know some people have had trouble with the AF motor dying, but it won't focus correctly even in manual focus. Everything looks great through the viewfinder, but it looks like crap on the sensor.

The 50/1.4 does hunt under low-light conditions and the target you gave it doesn't look to be sufficiently lit or of sufficient contrast for good focus lock. Try stopping down just slightly (f/1.6 or f/1.8, for example) to see if that makes a difference. Also, keep in mind that at f/1.4 your DOF will be razor thin - it won't take much to miss.

For manual focus, make sure your viewfinder diopter is correctly set. If it's off than what appears sharp to you through the viewfinder will indeed be out-of-focus on the sensor.

Thanks for the tips. I'll mess with it some more and see what happens.

Now that I think about it, all of my shooting lately has been in low light, so it may just be the lens struggling.