two coin images (images added)

Litonotus · Post by **Litonotus** » Tue Feb 19, 2013 1:01 pm

I have no natural samples now. I have to wait for spring /:

Today I tested Ikea led lamp, it works good as a reflected light source, so I decided to take some images of a polish coin, a first thing that comes into mind when playing with reflected light.

I still have to do something to avoid that white 'holes'. I used a piece of foil as a diffuser here.

I used a piece of paper as a diffuser in this case.

Baley · Post by **Baley** » Wed Feb 20, 2013 6:46 pm

They look good. Could you post a picture of the LED lamp positioned for use on your microscope?

pwnell · Post by **pwnell** » Sat Feb 23, 2013 12:49 pm

First one especially is quite nice. Think you handled most of the specular highlights well.

Litonotus · Post by **Litonotus** » Mon Feb 25, 2013 10:40 pm

thank you (:

the lamp looks like this but has a clamp instead of a circular base. llight angle was about 30 degrees.

Litonotus · Post by **Litonotus** » Mon Mar 04, 2013 10:45 pm

2 zl again.

I tried again but still the highlight has no details, jus a white spot... what to do? I have to say I used high iso 800-1600, maybe I should try lower?

2 euro looks better.

rjlittlefield · Post by **rjlittlefield** » Mon Mar 04, 2013 10:51 pm

The problem is that the specular reflection is just very bright compared to the rest of the coin. You may have to take several photos at different exposures and combine them using some HDR tool. There is one in Photoshop, or in a pinch sometimes PMax in Zerene Stacker will do the job.

--Rik

Charles Krebs · Post by **Charles Krebs** » Mon Mar 04, 2013 11:51 pm

The bright ridges are so well-defined and specific in the coin shot that I don't think you even need to resort to HDR. Just do a second set of shots specifically exposed for the reflection. Layer them in post-processing and use the "darker" version where needed.

It is rather common that I find a need to do this with darkfield on the microscope, since often there is one area that is simply far too bright when the best overall exposure is used.

Litonotus · Post by **Litonotus** » Tue Mar 05, 2013 10:39 am

thank you very much, I will try that (:

Litonotus · Post by **Litonotus** » Tue Mar 05, 2013 12:05 pm

it works, I overexposed the image and the highlight is better, than I put together two images; problems begin when it will come to a stack...

In high school where I had 3 years of traditional photography and I remember that there WAS a solution for that highlight problem (without processing of course), unfortunately I do not remember it now, and also many traditional tricks do not work when it comes to digital imaging.

rjlittlefield · Post by **rjlittlefield** » Tue Mar 05, 2013 12:14 pm

Litonotus wrote:many traditional tricks do not work when it comes to digital imaging.

Just curious, what tricks are you thinking of?

--Rik

rjlittlefield · Post by **rjlittlefield** » Tue Mar 05, 2013 12:24 pm

Litonotus wrote:I remember that there WAS a solution for that highlight problem (without processing of course), unfortunately I do not remember it now

Are you thinking of "burning in"? This was a darkroom technique to recover detail from dense parts of a negative by giving them a longer exposure during the printing step. If you're talking about something to be done in setting up the shot, then I don't know any solutions other than careful lighting and sometimes use of polarizers (not applicable here with a metal subject).

--Rik

Litonotus · Post by **Litonotus** » Tue Mar 05, 2013 12:51 pm

Just curious, what tricks are you thinking of?

It was many years ago... first step was 'playing' with developing a negative - changing both times and density of the developer gave many interesting effects (very fine grain for example). I remember that both me and my friends had very good results, but I do not remember details today.

second was when images were developed/printed, and yes, burning was one of very useful things in cases like we are discussing here.

that was a different way of thinking...

rjlittlefield · Post by **rjlittlefield** » Tue Mar 05, 2013 1:45 pm

Litonotus wrote:that was a different way of thinking...

Indeed. The tricks you mention have been replaced by a completely different set of tricks having to do with choosing ISO & exposure when you shoot, then changing the "development" parameters in raw conversion, followed by levels/curves adjustment.

Shooting JPEG in camera is a lot like shooting slide film and having it commercially processed. There are not many options to play with, and if the highlights blow out, they can never be retrieved.

--Rik

Charles Krebs · Post by **Charles Krebs** » Tue Mar 05, 2013 2:03 pm

it works, I overexposed the image and the highlight is better, than I put together two images; problems begin when it will come to a stack...

(I'm guessing you meant "underexposed")

If you anticipate such a problem, it would not be that unusual to take separate stacks at different exposures (probably best to bracket at each step during initial stack acquisition) and then use the lighter or darker segments as needed (or go to an HDR method). Makes for a lot more work, but sometimes you just can't solve it with lighting.

If it is a high magnification stack where you know you will be turning off "re-sizing" in the stacking software, you can just go back and shoot the frames needed to record the the problem areas and stack and incorporate them as needed. This saves time and work if it is a very large stack and the trouble area is small. (For example, it is not unusual for me to do this with a small white patch of scales on an overall dark butterfly wing).

Litonotus · Post by **Litonotus** » Wed Mar 06, 2013 1:07 pm

thank you for all suggestions (:

Charles Krebs wrote:
it works, I overexposed the image and the highlight is better, than I put together two images; problems begin when it will come to a stack...
(I'm guessing you meant "underexposed")

I ALWAYS (even in polish) confuse that two terms...

I know many PS tricks, but have no experience with raw files...