Neutral Density filter and Strobes

[bc_69]

New to LF and this site.

When I bought a Horseman 450 EM it came with a few lenses. I also bought off the same seller two medium strength strobes with umbrellas.

The studio I have set up to do portraits and still life is small so the strobes are reasonably close to the subject giving off a strong illumination even at low settings. Some early images showed hot spots so I thought about using a Neutral Density filter to help minimise the problem. Does that sound logical? Or I could put something like material in front of the strobes to reduce their strength.

Thanks

[Yo' Vinny]

I've stuggled with this as well. :-)

You can use neutral density filter material in front of the strobes, but be careful how you place it because it can both inconsistently affect the density of the light depending upon the light modifier as well as potentially melt under high strobe heat.

You can also use a neutral density filter for the camera lens, just keep in mind that focusing will be a challenge after that. Have a neutral density filter for the lens can also allow you to open the lens aperture if the combined ambient and strobe are too high and you are looking for a more narrow depth of field, but are already at the highest shutter speed. A neutral density filter for the lens can also alter light intensity of ambient in such a way that it is easier to carve your photo where strobe light hits, effectively creating for good low-key images.

[Jac@stafford.net]

An ND filter only lowers overall intensity. It will not selectively diminish hot spots.
A scrim or light box in front of the flash should help.

[Doremus Scudder]

An ND filter only lowers overall intensity. It will not selectively diminish hot spots.
A scrim or light box in front of the flash should help.

... or use umbrellas or reflectors so the strobes are not pointed directly at your subject.

Easy...

[bc_69]

Thanks for the tips. I have used the umbrellas and moved them further away to weaken the light strength which has worked to some extent but that has other consequences as well such as darkening the subject. Because the lens is wide open to give me shallow depth of field to blur the background, and it is a barrel lens to boot, it gets complicated. Using scrim was something I considered, or honeycomb grids was something else I found out can be fitted to the flash units which I will look into I think. Practice makes perfect but your feedback will be helpful and limit my wasted film.

With the ND filter it crossed my mind that it would not eliminate the highlights, and if it did it would dull the other parts anyway which would defeat the purpose.

[Jac@stafford.net]

Lighting is everything in the studio.
Adjust ratios, squelch highlights, fill shadows as necessary.

David L. Brill, a retired National Geographic photographer who has an almost exclusive relationship with the Smithsonian for photographing hominid skulls (http://www-personal.umich.edu/~feliks/people-of-bilzingsleben/images/tn_HerectusPekingWtTE_courtesy-of-David-Brill7-11-06_h1000.jpg) and bones invented a highly sophisticated lighting system. He shoots 4x5 and 8x10 using a few lights, and literally dozens of tiny mirrors on flexible stalks to squelch highlights, fill shadows as he wishes (http://ecx.images-amazon.com/images/I/61eyEeSqezL._SL1000_.jpg). Nobody does it better.

None of the web displays of his LF chromes does justice to the originals, of course.

[bc_69]

Lighting is everything in the studio.
Adjust ratios, squelch highlights, fill shadows as necessary.

David L. Brill, a retired National Geographic photographer who has an almost exclusive relationship with the Smithsonian for photographing hominid skulls (http://www-personal.umich.edu/~feliks/people-of-bilzingsleben/images/tn_HerectusPekingWtTE_courtesy-of-David-Brill7-11-06_h1000.jpg) and bones invented a highly sophisticated lighting system. He shoots 4x5 and 8x10 using a few lights, and literally dozens of tiny mirrors on flexible stalks to squelch highlights, fill shadows as he wishes (http://ecx.images-amazon.com/images/I/61eyEeSqezL._SL1000_.jpg). Nobody does it better.

None of the web displays of his LF chromes does justice to the originals, of course.

Thanks Jac, I'll check out that site, I'm always interested to see and learn from those that have mastered the process. You're right about how lighting is critical in the studio, it is such a precise discipline indoors, there is nowhere to hide.

[bc_69]

Well those skull shots certainly have an air of glowing quality, do you know what type of camera and lens he used, and film? The evenness of the clarity is sublime, he obviously knew his craft extremely well. Getting to that level is probably out of my reach as a part timer but getting just close would be an achievement for me.

[Greg Miller]

I have used the umbrellas and moved them further away to weaken the light strength which has worked to some extent but that has other consequences as well such as darkening the subject.

Moving lights further away from the subject makes the light harder, which would make hot-spots worse. You need the lights closer to the subject to soften the light. If the light is too bright for the desired f-stop, then you need to eliminate light with ND filters, diffusers,... It's hard for me to imagine a strobe that is too bright at low settings for LF though.

[Jim Noel]

Turn the strobes around and bounce them off the walls. This willl attenuate the light and diffuse it eliminating hot spots.

[vinny]

Moving a light further from the subject doesn't make it harder but it does make the effective source smaller. A larger source wraps around the subject and softens gradations between highlight and shadow. Try putting the source in as close as you can while hanging a piece of bleached muslin or white ripstop in front of it. Heavy diffusion like this will cut down the intensity while creating a very soft glow. The issue then can be dealig with the extra light that spills onto your background. we often use large (12x12ft honeycombs) directly on the diffusion to keep extraneous light off everything but the subject. you can do this yourself on a much smaller scale if you like. Greg, I believe we're saying the same thing but I just like to use the proper terms.

[bc_69]

Ok thanks for the helpful feedback, there is plenty of ideas to try, I'll keep experimenting until I get the result I am after. I have got muslin and a ND filter, I'll give both a try and post the results.

[bc_69]

Greg, that sounds like an idea, with so much on the net now it can sometimes be overpowering and confusing, but I'll check it out.

[Lightbender]

Lighting well with strobes is extremely difficult unless you have something to test with. Used to be polaroids. Now digital is your friend for this.
-for really diffuse lighting, bounce off the walls.
However, if you are in a small area, the walls may reflect so much the subject can look flat. (this will happen even if the lights are in a softbox pointing at the subject)
A ND filter over the lens will not help. Dimming the flash or using a ND filter on the flash will not help either. (there will still be 1 stop less light at each interval)

Its all about A. the distance from the light source and B. the surrounding light.
You can put the source close to the subject for extreme light falloff (and hotspots), or far away for more even light.
You can control the shadows with either additional lights, or more diffusion.

You can also get an idea of the result with a flashmeter by rotating it around. First pointing at the camera, then turn it 90 degrees. if you have a dome style meter, try it again full 180 degrees.

[bc_69]

Cheers Lightbender, Moving the light further away looks to be the answer, plus I'm going to reduce its intensity. I've been reading Mortensen's Pictorial Lighting which I have found fascinating and he recommends the same approach. See how that goes and keep experimenting, another thing Mortensen is big on, do as many samples as possible until you get it right he writes, obviously he didn't have to pay what we do for film, lol.

BC