Apologies in advance for what may be a dumb question(s) . . .
Are all of these tests using autofocus? Assuming yes, then
- You say the focus target was the focusing chart. Did you use the
viewfinder and/or liveview to verify that the system was focused on the target?
And not on the numbers on the ruler or some other point?
- What happens with the same setup if you manually focus?
I am trying to grapple with what are the possible failure points in the AF
process . . .
stan
On Mar 9, 2013, at 3:09 PM, Larry Colen wrote:
> Please excuse if multiple copies of this come through. My friend upgraded
> the server that he hosts my account at, and things have been completely hosed
> and unreliable for the past week. All morning mac mail has been insisting
> that the smtp server is offline, and hasn't let me correct that.
>
>
> The night before last I had a whole series of photos of a musician front
> focus on his microphone, despite it being no where close in the frame to the
> focus point. The light was reasonably bright, but it was tungsten. So,
> tonight, being the nerd that I am, I decided to test how color affects
> focusing.
>
> I took assorted gels that I had around, and also a couple of green bulbs set
> up a few test setups. As far as I could tell under red light the K-5 did
> front focus. It also seems to front focus under blue light. For this run
> of the test. I tried to defocus the lens between each shot.
>
> Shot using tungsten, blue gel, yellow gel, CTO gel, red gel, green
> incandescent, and a green CF bulb. Focus point set on the focusing chart.
>
> I haven't done a test yet to determine whether it just front focuses under
> low light, or whether it front focuses because of lack of light in the green
> channel.
>
> ISO 80, 77/1.8 wide open, shot at 1.8, attempting to keep exposure even. I
> also processed each shot both as color and black and white.
>
> Crops:
> http://www.flickr.com/photos/ellarsee/sets/72157632954496070/
>
> Crops on fluidr
> http://www.fluidr.com/photos/ellarsee/sets/72157632954496070/
>
> Uncropped:
> http://www.flickr.com/photos/ellarsee/sets/72157632950174733/
>
> On thursday night we had me with the K-5, Danielle with a D700, Michael with
> a 1D4 and Scott with an OM-D. It'll be interesting to compare everyone's
> photos. Mine, I'm afraid, did not turn out well.
>
> Apparently both Danielle and Igor think that I obsess a bit too much on
> monopods for low light work.
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