Search found 4580 matches

by Lou Jost
Sun Jan 24, 2016 9:01 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Best Photoshop spot removal options for stacking?
Replies: 19
Views: 5146

Asha, yes, but it is far more tedious and can't be automated. A hot pixel shows up on a stacked image as a curving dotted line (sometimes with a cloud of blur around it). The curve depends on the alignment of the images, the number of images used, the spacing between them, and the exact wiggly path ...
by Lou Jost
Sun Jan 24, 2016 8:40 am
Forum: Photography Through the Microscope
Topic: Antenna of an ant
Replies: 10
Views: 2008

"I realize that I need a better screen to be able to see the purple." Screens matter very much. Sometimes a wide-gamut screen with a lot of saturation can be very useful for judging color problems. Other times a very low-contrast screen with a low gamma value can reveal otherwise-invisible problems...
by Lou Jost
Sat Jan 23, 2016 5:44 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Best Photoshop spot removal options for stacking?
Replies: 19
Views: 5146

Best Photoshop spot removal options for stacking?

I am making a Photoshop action to remove spots caused by sensor dust prior to stacking. I'll open the RAW file as a .tif and then use the spot healing brush to remove all dust spots and hot pixels. There are three options: "context aware", "create texture", and "proximity match". All sound appealing...
by Lou Jost
Sat Jan 23, 2016 5:38 pm
Forum: Photography Through the Microscope
Topic: Antenna of an ant
Replies: 10
Views: 2008

Thanks...looks like there is a very slight purplish cast to the dark background details in the non-filter sample, which is not present in the filtered sample. Interesting to know about this option anyway.
by Lou Jost
Sat Jan 23, 2016 11:31 am
Forum: Equipment Discussions
Topic: Extension tubes on a Nikon 10X
Replies: 9
Views: 1786

Chris, I don't have resolution targets (other than my favorite white butterfly scales on my reference butterfly wing...) so I can't be very precise about it. I made that post when I was just getting started in this. My subjective impression now is that the small sensor shows significantly more fine ...
by Lou Jost
Sat Jan 23, 2016 10:44 am
Forum: Equipment Discussions
Topic: Extension tubes on a Nikon 10X
Replies: 9
Views: 1786

Rik, I did both kinds of tests. Here http://www.photomacrography.net/forum/viewtopic.php?t=28930&highlight= I showed that a Sony HX400V bridge camera , when it is used at 200mm with a Mitu 10x, reveals considerably more detail on the subject than I can get out of a Nikon D90 APS sensor. This means t...
by Lou Jost
Sat Jan 23, 2016 7:47 am
Forum: Equipment Discussions
Topic: Extension tubes on a Nikon 10X
Replies: 9
Views: 1786

You already have enough pixels to get all the detail a 10x NA 0.25 objective can collect. ChrisR, are you sure about that? My results with a Panasonic bridge camera vs a Nikon APS-C camera showed that one could get much more detail out of a 10x lens by increasing the pixel density on the sensor. I'...
by Lou Jost
Fri Jan 22, 2016 12:55 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: epi cross polarization purple highlights
Replies: 9
Views: 2573

What often happens under those conditions is that relatively more purple/blue light gets through the crossed filters, leading to a change in the light color. It's the same effect that Lou Jost is talking about. If you do the test that Rik suggested, and if it turns out that blue and purple leak thr...
by Lou Jost
Fri Jan 22, 2016 10:36 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: epi cross polarization purple highlights
Replies: 9
Views: 2573

dlg, I was referring to visible violet, not UV. Get rid of the violet light and you should also get rid of the violet highlights.
by Lou Jost
Fri Jan 22, 2016 8:34 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: epi cross polarization purple highlights
Replies: 9
Views: 2573

In my experience, most photographic polarizing filters are not not 100% efficient at short wavelengths. A good way to fix that is to eliminate the short wavelengths in your light source. The "fringe-killer" astronomical filter discussed in a recent thread might fix this completely if that is the pro...
by Lou Jost
Tue Jan 19, 2016 9:12 pm
Forum: Photography Through the Microscope
Topic: Antenna of an ant
Replies: 10
Views: 2008

As I understand it these filters are just cutting out the highest and lowest wavelengths to minimize chromatic aberrations in non-apo lenses. Since your lens is an apo, it makes sense that you would not see any effect except a color shift. But it would be interesting to try it on a cheaper non-apo l...
by Lou Jost
Tue Jan 19, 2016 8:58 pm
Forum: Photography Through the Microscope
Topic: Lecanora chlarotera
Replies: 8
Views: 1025

The cell phone image is my favorite!
by Lou Jost
Sun Jan 17, 2016 7:07 pm
Forum: Photography Through the Microscope
Topic: Gold Bugs
Replies: 9
Views: 1152

These are magically beautiful! Thanks very much for sharing the story and the images. I wish I could figure out how to sputter-coat my plant specimens like that; I don't need SEM-level resolution but I need to make my subjects opaque and ideally rigid.....
by Lou Jost
Sun Jan 17, 2016 4:22 pm
Forum: Equipment Discussions
Topic: Suitability as a tube lens
Replies: 33
Views: 3314

Yes, excellent. That is a very good sign.
by Lou Jost
Sun Jan 17, 2016 1:11 pm
Forum: Equipment Discussions
Topic: Any advice on cheap flashes
Replies: 30
Views: 3125

If there is NO delay, the bright flash dominates the exposure.

If the delay is too long, then the fall of the second shutter curtain will block the flash's light from some part of the sensor.

As I said above though, the delay with the Yongnuo's optical slave is completely unimportant.