Lightbox advice

Ajf350d

Ajf350d

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Initial thoughts on the design in the link.
I'd make the interior of the box white to help distribute the light and maintain an even colour temp. (The link looks like a cream colour.)
I'd make the sides deeper to reduce the chance of bright spots due to the proximity of the LEDs to the diffusing surface.
Regarding the Plexiglass sheet, I'd probably go for a gloss finish for ease of cleaning, but matt the inside surface myself with a fine grade emery paper on an orbital sander.
In the link he's got a continuous rope of lights resulting in obvious bright spots along the top and bottom edges, it should be quite easy to cut and bridge to create straight runs.
Finally I'd want to see samples of the lights before installing them. "Cool White" can be very cool indeed, almost blue.
 
Can I ask why you want to make it in the first place? Why do you need one?
I find it difficult to see what it can do that can't be done better with something entirely different - for example, if what you want is an underlit surface to photograph objects on, then a sheet of acrylic lit by a flash head in a softbox would be better in every way. And if you really do need a lightbox, then powering it with strips of LED's that are not designed for photographic use will produce terrible colour reproduction (they will have a very low CRI) and it can be done much better with fluorescent lamps, some of which have a reasonable CRI.

CRI is something that is normally either ignored or lied about by sellers, but it really does matter.
 
Garry Edwards said:
Can I ask why you want to make it in the first place? Why do you need one?
I find it difficult to see what it can do that can't be done better with something entirely different - for example, if what you want is an underlit surface to photograph objects on, then a sheet of acrylic lit by a flash head in a softbox would be better in every way. And if you really do need a lightbox, then powering it with strips of LED's that are not designed for photographic use will produce terrible colour reproduction (they will have a very low CRI) and it can be done much better with fluorescent lamps, some of which have a reasonable CRI.

CRI is something that is normally either ignored or lied about by sellers, but it really does matter.
Click to expand...
:agree: With my reply I was assuming it was for "Slide viewing" or similar, not actual photography.
 
Yes, it will be usable for your purpose, but IMO it has NO advantages over flash.

Your link includes a huge number of innacurate statements, they guy obviously considers himself to be an artist who is too good at art to need to understand anything about the qualities of the medium that he is using - light :)

Here's an example What is the best light source for a light box that will be used for photography? We’ve had good luck with daylight-balanced fluorescent tubes and with LED lights. According to Harold Davis, “Assuming you are shooting RAW, the color temperature of the light source for light box flower photography is surprisingly unimportant, because this can be adjusted in post-production. I have seen good results from a wide variety of light sources.”
Now, that statement isn't in itself wrong, but what is very wrong is that he doesn't seem to understand the difference between colour temperature, which is easily adjusted, and colour rendition index, which needs to be pretty high if colours are to be captured reasonably accurately.

Incidentally, his technique seems to owe more to PP than to actual photography - nothing actually wrong with that, but unecessary with good technique.
 
Thank you.
I understand what you say and there may be better ways of building the box using different types of light.
The main advantage I thought over flash was that being constant light you can see roughly how an arrangement looks without constant test photos, and also I would guess that using flash is going to require a larger user area to be able to stand a perspex (or similar) sheet high enough above flash to to get reasonable spread of light?
Both are major considerations for me, plus I only have a small Yongnou flash so not sure that would even be suitable? I also have troubles with technique with flash, but that's for another day!

The link with the technique I wanted to try is off the back of a post I put in post processing regarding Mandy Disher, who seems to use a similar technique.
I guess both are closer to are than plain photography!

Regards LEDs, you can get high CRI ones if you shop around, albeit not cheap. As a guide though what is considered good?
I've seen 80+ ones.
 
Personally I would just place a piece of acrylic on top of a softbox. If you only have a little hotshoe flash, then build a simple box, paint the inside white and put the flashgun inside, bouncing the light off of the opposing side - 2 flashguns would be better and 4 would be better still, because the light would be much more even, but one will do.

A CRI of 80 isn't nearly enough, you should really be using about 95, which are obtainable but expensive.
Be warned though, although photographic quality ones ARE available, the vast majority of the ones that are claimed to be of photographic quality are total crap and the sellers claim false figures, secure in the knowledge that very few people are able to check the veracity of those figures.
 
@Ajf350d: Plexiglass is just a trade name for acrylic. There are any number of UK suppliers of acrylic sheet but I can recommend Amari Plastics and (surprisingly) Blackburns Metals - both have depots scattered around the country.
 
Thanks both again.
I struggle with flash and rarely get consistent output so I tend towards fixed lighting hence this option over flash.
Perhaps I will evaluate my options again....

I will check out those two suppliers and see which is the best. I understand Plexiglass is a brand name, but wasn't sure if the specific #2447 was a special type at all as it seems to be used on;y for these types of products etc.
 
Ajf350d said:
I struggle with flash and rarely get consistent output so I tend towards fixed lighting hence this option over flash.
Click to expand...

We can help with that. The first step is to put everything - except focusing - in manual.

Garry Edwards said:
Incidentally, his technique seems to owe more to PP than to actual photography - nothing actually wrong with that, but unecessary with good technique.
Click to expand...

Very much so. I haven't watched the webinar but he seems to be bracketing and blending layers manually in order to get both the translucency and the high contrast. I'd have guessed that if you got the exposure spot on you'd only need to tweak the contrast and saturation to get the same effect - backlit images can often lack contrast. Maybe @Garry Edwards has some suggestions for how you might get results like this straight out of camera?
 
juggler said:
We can help with that. The first step is to put everything - except focusing - in manual.



Very much so. I haven't watched the webinar but he seems to be bracketing and blending layers manually in order to get both the translucency and the high contrast. I'd have guessed that if you got the exposure spot on you'd only need to tweak the contrast and saturation to get the same effect - backlit images can often lack contrast. Maybe @Garry Edwards has some suggestions for how you might get results like this straight out of camera?
Click to expand...
I don't think that it's possible to get the best possible results without SOME degree of PP work, and there's no reason to avoid PP anyway - but as I've said earlier, I think that excessive and unecessary PP work is being done as a poor substitution for good technique. Before we had digital, I photographed similar items on transparency with no option to do any form of PP, so I know that at least 90% can be done in camera, with a single shot.

My starting point would be to use flash to get adequate and consistent power and perfect CRI, shoot in raw and get the exposure right, so that the pure whites are "nearly" pure white, and this level of exposure will avoid destroying the fine detail in the flowers (or whatever) Then, at the raw stage, adjust saturation as required, set colour balance, and set clarity to something like 50% (which helps enormously with local contrast).
Then, under image/adjustments/selective color/whites, get the background as white as required.

Simpler and better:)
 
Ajf350d said:
Thanks both again.
I struggle with flash and rarely get consistent output so I tend towards fixed lighting hence this option over flash.
Perhaps I will evaluate my options again....

I will check out those two suppliers and see which is the best. I understand Plexiglass is a brand name, but wasn't sure if the specific #2447 was a special type at all as it seems to be used on;y for these types of products etc.
Click to expand...

2447 is a colour shade - there will be an EU equivalent and either company will sort that for you.
 
thanks :)

I will have a better attempt at using flash again too.
Part of my issue is probably the flash I use is not on camera so the output has to be set manually - a left over from my swap from Canon to Olympus M43
I do have Sekonic light meter that can measure a given output and show the required exposure on the camera but it never quite gets right. Triggering is by an IR sender/receiver.
I also struggle with things such as consistent spread of light and avoiding harsh shadows.

I'll perhaps start a separate post about this again - I think I have posted on that topic before!
First step maybe to get the Olympus flash?
I haven't room for studio type flash unfortunately.
 
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