Specular Highlights

I'm on this lesson http://strobist.blogsp​ot.com …2-specular-highlight.html

but I can't quite understand it, to keep your highlights from blowing would you want to spread out the light more or keep it concentrated?

I tested it out myself and couldn't really see a difference whether I had the flash at 24mm or 105mm.(Shooting a watch 3ft away through an umbrella at camera right 45 degrees down.)

The wording on that post is kinda confusing.

I think that article is telling me to reduce specular highlights I should make my light source larger, not smaller as in concentrating the light. You mention spreading the light. That just means more of it is going off and is not doing anything. Soft light is all about the size and distance of the light source to your subject. I'm not an expert on controlling specular highlights but my guess is the last thing you would want to do is concentrate the light source. Also there are soft boxes with baffles to prevent hot spots. Interesting to follow this.

Spreading light just does this.

maverick75 wrote in post #16037583
I'm on this lesson http://strobist.blogsp​ot.com …2-specular-highlight.html

but I can't quite understand it, to keep your highlights from blowing would you want to spread out the light more or keep it concentrated?

I tested it out myself and couldn't really see a difference whether I had the flash at 24mm or 105mm.(Shooting a watch 3ft away through an umbrella at camera right 45 degrees down.)

The wording on that post is kinda confusing.

Specular highlight is the direct reflection of your light source and will be the brightest part of your image. And usually, there's not much you can do to keep it from blowing out if the surface of the object is very reflective. If you do, the rest if the image will be grossly under exposed. What you do want to expose correctly is the diffused highlight area.

The smaller the light source, the brighter the specular highlight is going to be. So, if you want to control it, you want to make the light source as large as possible. This isn't done by changing the light beam spread as you described but by physically changing the apparent size of the light source. You can increase the apparent size of the light by using a large softbox or umbrella. You can even bounce the light off the ceiling or walls. The idea is to make it look like the light is coming from many different direction rather than from one point.

Thanks! I understand now, even went back and re-read what I didn't understand and it makes more sense.

wait a minute....

isnt a specular highlight always the same intensity it doesnt matter if you bring it forward or back it will always be the same intensity, the thing that allows you to control the specular highlight is its relative intensity versus the diffuse. meaning, if your specular is at f16 and your diffused is at f4, if you bring the light closer to the subject your specular is still f16 but youve raised your diffused to f8 so now instead of having 3 stops difference between the diffused and specular you only have 1 stop difference thereby "taming" the specular intensity.

edit: i see leo has explained it before my post hehehe......albeit in different ways since i mentioned just controlling relative exposures while his includes bouncing and apparent light sources

ccp900 wrote in post #16037960
wait a minute....

isnt a specular highlight always the same intensity it doesnt matter if you bring it forward or back it will always be the same intensity, the thing that allows you to control the specular highlight is its relative intensity versus the diffuse.

A large light source will have a lower light density. I.e. every cm2 of the light source will send out less light. But the total amount of light reaching the subject will be the same since there are a larger area that is emitting the light.

That also means that a large light source will give you a larger specular highlight, because the large light source can be seen as millions of small light sources differently located. And every one of them are weak. And every one of them have a slightly different location, so they will generate a small highlight at a different location on your subject because the angle from light source to subject is different.

So a large light source will give you a large, but weak, specular hightlight.

A small light source - like a laser - will produce a tiny, but very strong, specular highlight. The example with a laser is extra interesting because that little specular highlight can be strong enough to cut through objects if the laser is strong - but still way weaker than a single studio light.

i wasnt able to read the blogspot link since i was at work but now that ive read it, i can see that we are talking about 2 different things. The link talks about controlling the specular intensity by essentially diffusing it and spreading the light evenly across a bigger medium which thereby changes the real size of the light source. what happens here is that you spread out your light to become a bigger source and since you spread it out you lose intensity measured on a per unit of area.

the concept i typed above is more around controlling the intensity of the specular highlight given that you cannot change the real size of the light source, the trick here is you can control the relative size of the light source allowing you to control the amount of light falling on the subject but keeping the intensity of the actual specular highlight the same (since it wont change based on the distance of the light source to the subject - a specular measuring f8 at 10 feet will still measure f8 at 8 feet).

in the experiment i think the reason there was no perceivable change is that the distance between the light source and the watch is so near that when the speedlight was zoomed it really didnt affect the size of the specular being reflected in the watch, meaning the watch wasnt really big enough to show the true size of the specular as the size changed, something like a 5 ounce can taking in 100 liters of water and then the same can taking in 50 liters of water, there is just too much water.

pls correct me if im wrong though since we are all trying to learn