Photo review plus strange occurrence.

[owen]

Hi guys.

I was at a CD launch at the local library tonight and here's one of the shots I took:



what do you think of the B&W conversion?

My question is, note the fluro lights in the top right corner, one edge of them is razor sharp, even in the full sized version. Given that everything else at this distance is OOF, what would cause this?

Regards,
Owen.

[TonyH]

Hi Owen,

is the flouro light razor sharp or blown out exposure?

Regards

Tony

[Onyx]

Just coincidence I think Owen.

I don't think this is the ideal B+W conversion, as the singer's face falls in the shadows and consequently looks a little muddy. I don't know which method you used, but try another one. I could suggest blue channel desaturate, as I've had some success with that - in low light conditions where the blue channel is noisy (this image doesn't look particularly high ISO/low light-ish).

[owen]

I'll have another go with that Onyx.

The method I used was convert to lab, delete the a + b channels, convert back to rgb and then add a bit of contrast.

I'll try what you suggested and see what happens... I haven't done too many black and whites before



Cheers,
Owen.

[owen]

Tony, the light is blown out, however one edge of it is out of focus and the other long edge is sharp, I don't really know why it would do that.

Regards,
Owen.

[owen]

Do you think this is any better?

[paulvdb1]

I think you're just the victim of bad lighting in the library

Nothing much you could've done short of being in a different position - like his left instead of his right

[Onyx]

Owen, I just had a lightbulb over my head moment...

The rendering of the sharp fluro light edge could be relatd to the MTF chart characteristics of the lens in use.

OK, picture concentric circles starting from the lens' point of absolute centre. Detail running outwards from the centre corresponds to the sagital lines in the MTF chart of the lens, and details perpendicular to these running around the concentric circles are the meridonial lines.

If the resolving power along the sagital and meridonial axis of the lens used for this image differ greatly, this would lead to the OOF/bokeh elements taking of varying degrees of unsharpness along the two axis as observed. This is my hypothesis for why the light in the background seems to have the long edge 'sharp'.

Here's a primer in modulation transfer functions for what I'm referring to:
http://www.luminous-landscape.com/tutor ... -mtf.shtml

[owen]

Hey Onyx, that lightbulb you found sure is confusing! I think you're right though as what you said was very technical.


Actually I just read over that link and understood most of it, but I am not sure how it would relate to having a sharp defined line in an out of focus area.

I'm happy to say that it was an anomally and ignore it.. or better yet I might even clone it out... maybe put a ceiling fan in it's place or something like that lol

Thanks Onyx.

[mudder]

Prefer the second shot with more detail of the artist, wondering whether it might be worth trying to just raise the "lightness" on the artist only and leaving the background slightly darker? Just a thought for keeping viewer focus on the artist and keeping the busy background from distracting...

Just thinking aloud...