Newbie need some Critique and need help on background color

[leekekhuan]

so this is my 3rd try and result is better than last week, but still i am no where near to those high res shot. Is my objective is not good enough to get any better resolution at .01mm stacking? does it mean expensive objective = better detail result?

I also tried different background and found to much color overcast, should i fix it in Photoshop or is there anyway to reduce to much color overcasting?

Thank you in advance.
Here are pictures with different background





This was worst background




BTW here is DIY diffuser, result i much better than the diffuser i bought for 35$.
It is mouthwash bottle, i cut out base and part of bottle to cover the subject. I am waiting for wimberly plamp to hold it without put it on the objective and flash stand. I use this after looking at John Hallmén diffuser, but he mounted on lens and i am having issue to do same way

[Olympusman]

I would say the color casting is the color of the background card reflecting off the shiny front surface of the objective. Try shooting through a small hole in a black card and see if there is any improvement.

Mike

[rjlittlefield]

I think those are the most extreme color casts I've ever seen.

Mike's suggestion of shooting through a black card is a good one. Just be sure that the hole is centered and is large enough that it does not block any of the glass. Blocking any of the glass will reduce the effective aperture of your lens, which may degrade the image.

A few other things to consider...

1. Make your background chip smaller and place it closer behind the subject. The less color there is inside your white illumination chamber, the better.

2. Be sure your camera is set on manual color balance, not automatic.

3. Temporarily place a small piece of white card in front of the subject and set a custom color balance from that. This will compensate for any stray color from the background. It will also compensate for any color shift that the diffuser might be introducing. Color shift from the diffuser is not causing your current problem, but some might become evident after you get the background shifts under control.

--Rik

[johan]

I'd agree, too much card influencing the subject. I'd try an experiment - try not using a background card at all and see what settings it takes to get good colour. Then use those identical settings with card behind and it'll show you the effect the card is having on colour cast overall. Then experiment with the colour card as Per Rik's suggestion #1. Forwards, backwards, angle it down, angle it up, make it smaller and nearer, larger and further back -- lots of experimentation to find a way to pick up the nice colour of the card without having it influence the subject.

One thing about that type of plastic is that when I've used it it creates a hotspot, which makes for quite a large dynamic range which is tricky to work with - especially in the darks.