SB800 vs Lencarta

roglowe

roglowe

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Roger Lowe
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Can anyone explain something to me.
I have 2 Elite pro 300 Lencarta units in my studio. Not a bad word to say about them. I like them.
However, pictures taken on my Nikon D80 with SB800 attached look much sharper then pictures taken with the Elite Pro 300 flash.

Can anyone explain this? I am a novice. :thinking:

Thanks
Roger.
 
You're not focusing correctly possibly due to the red target / focus assist on the SB locking things in where as studio heads dont have this facility
 
Rikki said:
You're not focusing correctly possibly due to the red target / focus assist on the SB locking things in where as studio heads dont have this facility
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I think that's a real possibility. The others are camera shake or subject movement, hotshoe flashguns have a much shorter flash duration when set to low power
 
Thanks guys. Rikki - Explain that to me please. Red Target?
 
The SB800 has focus assist, it emits a red light to aid the camera in focusing in lower than ideal situations.

Whats your shutter speed with the strobes, and what are you shooting?
 
Here are two examples. one with sb800 outdoors and one in studio with Lencarta lights.

http://www.lowesphotography.co.uk/flash.htm

I can't shoot higher than 1/160 in the studio with the lencarta lights.

You will see the girl is out of focus (hand held) and the guy is a lot sharper (hand held).

I can't figure it out.
 
Thanks for the help.
So the flare is causing the out of focus look?
 
roglowe said:
Thanks for the help.
So the flare is causing the out of focus look?
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Yes. Flare isn't inevitable with blown white backgrounds, but it's very common.

Ideally, to avoid it you need to
1. Make sure that there is plenty of distance between primary and secondary subjects (the person you're photographing and the background) so that the light intensity can fall off
2. That you only use the absolute minimum of light on the background (something like 0.7 stop overexposure is enough)
3. Arrange the lighting so that the lights strike the background at an oblique angle so that most of the light goes away from the lens, not towards it.
4. Use an effective lens hood
5. Make sure the lens is absolutely clean
 
Garry Edwards said:
Yes. Flare isn't inevitable with blown white backgrounds, but it's very common.

Ideally, to avoid it you need to
1. Make sure that there is plenty of distance between primary and secondary subjects (the person you're photographing and the background) so that the light intensity can fall off
2. That you only use the absolute minimum of light on the background (something like 0.7 stop overexposure is enough)
3. Arrange the lighting so that the lights strike the background at an oblique angle so that most of the light goes away from the lens, not towards it.
4. Use an effective lens hood
5. Make sure the lens is absolutely clean
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1) The distance was about 4ft.
2) I have no light meter. Must get one!
3) I need to get 2 more 300's and the background reflectors
4) I didn't have a hood on the 50mm lens.
5) It was clean. but good to know.

I did some work on a black BG tonight and image was crisp.

The flare tip has helped. Thanks all. :clap:
 
Would it be fair to say that using a hilite would most likely emphasis this problem? (not saying the OP is using one, but just curious...)
 
gman said:
Would it be fair to say that using a hilite would most likely emphasis this problem? (not saying the OP is using one, but just curious...)
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Yes
 
I think there is a bit more to it than flare, though that is certainly reducing the contrast a lot. And it's nothing to do with the Lencarta lights as such.

It looks to me like the point of sharpest focus is actually behind the girl's face. Plus the studio light is big and soft, compared to the outdoors portrait where the light from a small gun is very harsh, emphasising sharpness.

I also wonder what processing parameters were applied to the two images - sharpness, contrast, saturation etc. They can make a huge difference.
 
HoppyUK said:
No. Not if you use it properly. No difference ;)
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There's always going to be a difference, simply because the light from a Hi-lite (or any other softbox) is travelling directly towards the lens rather than bouncing off of a background at an oblique angle.

But I do agree that a Hi-lite, used properly, doesn't necessarily cause flare problems
 
The light travelling at an oblique angle off a regular background never reaches the lens - it bounces off to the sides. The light that travels directly forwards is the same, whether it comes from a HiLite or not.

You continual assertion that there is some kind of fundamental difference here does not stack up, either in theory or practise ;)
 
I feel a challenge brewing somewhere.....;)

Is this something that's possible demonstrating through some straightforward tests? It would appear there's a fair number of people using hilites and also those who use muslin so it could be a worthwhile test?
 
would the light coming out of a highlight not be diffuse light? scattered all over?
 
It's just something that Richard and I like to disagree on, we're both getting on a bit and getting grouchy, ignore us:)

Actually, Richard is right in practical terms in that it's perfectly possible to get good results with any kind of backlit background (leaving brands out of it), all it needs is a basic understanding of the qualities of light and a bit of care. Sadly though, a huge number of people seem to do it badly. Very badly.

In theoretical terms, what I think Richard is saying is that because of cosine effect, the same amount of light will reach the lens whether the light is transmitted through the background or is reflected from it but I disagree; with reflected light, although it is true that no light would reach the lens at an angle of say 45 deg if the reflective surface was a perfect mirror, we don't use mirrors as backgrounds and much of the light reflected from a paper or similar background does reach the lens, but doesn't cause the same problems (or more accurately, isn't likely to cause the same problems as transmitted light unless it's done very badly) because it isn't fired directly towards the lens.

In other words, I feel that transmitted light backgrounds can produce results every bit as good as reflected light backgrounds but most don't because more care is needed with them.
 
matty said:
would the light coming out of a highlight not be diffuse light? scattered all over?
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Yes it is, but that isn't really the issue.

The real issue is that because the design of the Hi-Lite allows the subject to be placed very close to the subject, people do just that - my guess is that most people buy it just because they don't have room to have the subject well in front of the background, and in any event Hi-Lites aren't very big so they can't have people very far away anyway.

With backgrounds lit by reflected light, people have to be some distance away, otherwise there's no room for the lights.

Light follows the principles of the inverse square law, losing power rapidly as it travels. If the subject and background are very close together then very little lighting power has been lost by the time that the light from the background reaches the subject, therefore it can easily destroy fine edge detail (hair mainly) and can cause flare.

The problem is amplified by digital cameras, because small digi cameras don't cope well with extremes of contrast, compared with negative film, and the problem get's even worse when people cling onto the 'principle' that was common when everyone was using film, that a white background needs something like 2 stops of overexposure to make it white. With digital, a half stop of overexposure is normally enough provided that the lighting is even, 0.7 of a stop is definately enough, more is likely to cause flare and edge degradation.

That's my view, I'm sure that others will disagree...
 
gman said:
I feel a challenge brewing somewhere.....;)

Is this something that's possible demonstrating through some straightforward tests? It would appear there's a fair number of people using hilites and also those who use muslin so it could be a worthwhile test?
Click to expand...

Haha! It's not a challenge I want to embrace ;) You mean, spend half a day setting up two identical shots only to show that there's no difference?

For what it's worth, I think Garry has got the inverse square law wrong (it's irrelevant in this case) and the Cosine Law really doesn't apply either. Light travels in straight lines, whether it's coming from directly from a HiLite or that part of the light reflected forwards to the camera/subject off a conventionally lit background. It's exactly the same stuff.

The light from a normal background that is reflected off at 45 degrees plays no part in it, but I will say that when using a conventional background in this way, there is so much light fired off the sides that in a domestic environment that gets bounced around the room and gives a lot of unwanted and hard to control fill-in. Advantage HiLite :thumbs:

There is the issue of wrap as Garry mentions, because HiLite's tend to be smaller and so the subject is necesarily closer to it, but that's a different question. Subjectively, I think that a fair amount of wrap is part and parcel of the high-key pure white 'look' and if you reduce it too much the subject looks like they've just been cut-out in Photoshop.

It's all quite a delicate and tricky balance to strike, and also subjective. Bottom line is that both methods work fine, but you have to know what you're doing either way.
 
So basically light is light whether it is being refracted through a hilite or being reflected off muslin?

So for easy counting, lets say it takes two 200ws lights to blow a muslin background to 100% but only one 200ws to blow a hilite to 100%...

Basically the amount of light heading into the camera from each background will still be pretty much the same because although we are applying different power levels, one method is reflecting light whereas the other is refracting and both materials have different light absorbing qualities and therefore reduce the volume of light accordingly?
 
Not sure you're talking about the same thing Graham.

HiLites are certainly efficient, as no light is wasted bouncing off the sides and it is all forced out of the front. But you still need two lights to fill them evenly.

The cosine law basically refers to the way light is reflected off different surfaces, such as shiny or matt, at different angles etc. But none of that is relevant here, because the only light we're interested in is what is coming straight at the camera. The rest of it, how much there is of that and where it has gone at various angles, according to the cosine law, doesn't matter.

So, if you were able to do an exact comparison (which would actually be quite difficult to do precisely) and had say both a white paper/mulsin background cut to exactly 6x8ft, surrounded by black velvet and properly lit from 45 degrees each side, and then a 6x8ft HiLite - then if the exposure levels are the same, the quality of the light should be identical.

The inverse square law has no bearing, as that is self-correcting according to distance, ie the background gets smaller in proportion to distance so brightness is maintained over the smaller area seen by the camera.
 
HoppyUK said:
The inverse square law has no bearing, as that is self-correcting according to distance, ie the background gets smaller in proportion to distance so brightness is maintained over the smaller area seen by the camera.
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Very true, but this isn't what I was talking about when I said

Light follows the principles of the inverse square law, losing power rapidly as it travels. If the subject and background are very close together then very little lighting power has been lost by the time that the light from the background reaches the subject, therefore it can easily destroy fine edge detail (hair mainly)
Click to expand...
The ISL is certainly relevant; regardless of the source of the light, if it only has to travel say 2" to reach the nearest part of the subject when a transmitted light source is used and say 8' when a reflected light source is used (because the process of lighting a reflective surface requires much more space than using a transmitted light source) then the amount of light reaching the subject and available to destroy edge detail is massive at close distances and is significantly reduced at much longer distances.
 
Sorry, wasn't sure if I explained it properly. What I meant is that with a hilite there is no reflected light going into the camera, only refracted because the light is passing through the hilite material? With the muslin, it's reflected light.

So I as just wondering that if the power of the background lights for each were set to light each background to the same level (I'm guessing one type would need more lighting power than the other due to the way they are lit) then you would still end up with the same amount of light returning to the camera either via refraction or reflection?

Basically, does it matter if it's light that has passed through material (hilite) or light which has reflected off something (muslin)? Will they both cause the same effect?
 
The front of the folder (label) is out of focus. The shot is taken at f9, this looks like a focus issue.

Options: You could tripod it, shoot it without the lights, confirm sharpness, flip it to manual focus and manual settings and add the lights.

Consider a ND filter, this might let you tone the background down a bit (assuming you are on the lowest power setting)

Use a hood, flag and reposition the lights

get a lot more distance between the subject and the background
 
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Thanks for the feedback.
I always seem to have this out of focus issue when shooting on a white BG.
I tried on a black BG today and got perfect sharp image. I was on a tripod too where as the image I posted was freehand.
Loooooooads to learn!
 
gman said:
Sorry, wasn't sure if I explained it properly. What I meant is that with a hilite there is no reflected light going into the camera, only refracted because the light is passing through the hilite material? With the muslin, it's reflected light.

So I as just wondering that if the power of the background lights for each were set to light each background to the same level (I'm guessing one type would need more lighting power than the other due to the way they are lit) then you would still end up with the same amount of light returning to the camera either via refraction or reflection?

Basically, does it matter if it's light that has passed through material (hilite) or light which has reflected off something (muslin)? Will they both cause the same effect?
Click to expand...

Yes.

And Garry, apologies, we were talking at cross purposes on the ISL thing and you're quite right there. Even though I think we both agree that the ISL doesn't strictly apply to such large light sources, the principle is there.

As you say, if your subject is close to the background, both the amount of wrap and the brightness of that wrap (and the potential for edge degradation) is considerably higher.
 
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