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Strobes with Manual Exposure


garry edwards

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This comes back to the point I made in your other thread, just a few minutes ago. http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00KJo9

 

Your camera must be set to manual. Auto exposure doesn't work with studio flash.

 

There shouldn't be a 'remaining 3-4 seconds' unless yo want to deliberately include a continuous light source. Set the shutter to 1/60th or thereabouts, measure the light with your flash meter and set the aperture to the indicated value.

 

That will give you a starting point.

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Doug,

 

Sorry, I didn't make myself clear. You MUST shoot in manual.

 

If you shoot in aperture priority the camera won't know you have flash and will set a shutter speed that probably runs into seconds.

 

If you shoot in shutter priority the camera won't know you have flash and will set the aperture wide open.

 

Whoever advised you that you can live without a meter is wrong, unless you have a lot of experience and are shooting tethered to a laptop, in which case a meter is a great help but maybe not an absolute necessity. Checking the LCD screen or the histogram is a poor substitute IMO.

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Some people feel that you don't need a light meter if you are shooting with a digital camera. The premise is that you can try an exposure then look at the lcd on the back of the camera and check out the image and histogram to determine if the exposure is correct.

 

You can do that with some degree of success but a light/flash meter will allow you to get the proper exposure and check lighting ratios and, if the meter also does spot readings you can place highlights or shadows and compare the difference between the two.

 

When using studio strobes you should use manual exposure. Set your ISO as low as it can go ie: 50 or 100 or 200 ISO, set the shutter to 1/60th and shoot several exposures at f 5.6, 8, 11, 16 etc. Pick the best exposure and use that until you change your lighting setup.

 

Your sample shot looks like you are using a normal lens and getting a good bit of perspective distortion when you point the camera down to include the bottom of the piece of furniture. Use a longer, slight telephoto lens which will allow you to move farther away from the subject and reduce that distortion. Then you can fix the remaining distortion in PS using edit-transform-distort.

 

You're also getting a lot of flair off the white background on the top of your subject. You'll have to either hang a black cloth in front of the background just above the subject to reflect black instead of white on the top of the piece or use something other than a white bkgd.

 

One last sugestion: your lights are not large enough and diffused enough so you are getting opaque white specular highlights on the front of the furniture instead of soft, translucent highlights. Larger, softer lighting would help.

 

If you don't want to deal with those highlights properly, try rasing your lights higher than the furniture and aiming them down from above. You could also try a polarizing filter on the lens but it's better to make usable descriptive translucent highlights that define the furniture properly.

 

Try some of these techniques and see if your results improve.

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Shoot in manual, not shutter priority, not aperture priority, not program. Manual.

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Set the shutter speed at the sync speed of the camera or a bit slower. Assuming there's not a huge amount of ambient light, the shutter speed is largely irrelevant. 1/60 will work fine to start with on any camera/flash combo.

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Now, your exposure is controlled by the aperture, the flash power, and the placement of your lights and modifiers. If you're shooting digitally, you may also control exposure by changing the ISO setting (if shooting film, you could always switch to a different film with a different film speed).

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Shoot some test shots, changing aperture until things look right.

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After you've got a reasonably correct exposure, try playing with the shutter speed, just as an experiment. You should find that 1/15, 1/30, 1/60, and 1/125 probably all work fine and give virtually indistinguishable results. Somewhere around 1/250 or 1/500, you'll see a darkening, perhaps only over half of the frame or so.

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As long as the shutter remains open long enough to capture the entire flash burst, and as long as it's NOT open long enough to capture very much ambient light, the shutter speed is irrelevant. After doing the experiment, you should see why it's possible to just set the shutter to 1/60 (or probably 1/125) and forget about the shutter speed. And that's why you must shoot in manual, so that your camera doesn't look at the ambient light and choose the wrong shutter speed for you.

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Forgive me if this is a stupid question, but how should I properly control a

strobe while shooting in manual exposure? Testing rented strobes today, I

thought that it was odd how long the exposure would take after the flash fired -

sometimes up to 4 or 5 seconds. Am I doing this right? If the flash lasts only

a split second, what provides the rest of the exposure during the remain 3-4

seconds? Should I be doing something different? I am shooting with a Nikon D80

/ ISO 100 f/5.6 mostly. Ultimately, the end result was decent, but could I be

doing something better? I'm attaching a sample shot that I took today with a

combined strobe and natural light. I would apprciate any input.<div>00KKjW-35481084.thumb.jpg.d0e75a420f1e08560624fda5d8a27c5d.jpg</div>

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Gary - I am tethered to a PC screen. I use a Nikon program called Camera Control Pro that allows me to see the images large size as soon as I take them. That said, and without a flash meter for the moment, should I still set the shutter speed first (while in manual mode) and then shoot several shots to get the correct aperture?
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Doug,

 

Just set the shutter speed to 1/60th and set the aperture to f/11. Then take shots at different apertures until you're somewhere near the right exposure.

 

You might like to read through the various Lighting Themes, to get a basic idea of how studio photography works. http://www.photo.net/bboard/q-and-a?topic_id=1824&category=Lighting+Themes

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Get a FLASH meter - you are getting paid for this, I presume, the least you can do is get the proper equipment (not to mention learn how to use it). I mean, have some respect for your clients.

 

Imagine if you hired someone to teach your son/daughter some classes, say HISTORY or something and this someone went to an HISTORY/teaching board/forum asking "how do I teach history to a child...and do I need to know history to teach it?".

 

How would you fell about that?

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Everyone - thanks for the detailed responses. Brooks - you mentioned larger lighting, how could I achieve "larger" lighting - with a soft box? Larger umbrellas? And how important is the strobe reflector in terms of either size or quality? With the strobes I rented the other day, the reflector was 7". How does anyone feel about Alien Bees products? They have a studio package with a good assortment of equipment for a reasonable price, but I also want a kit I can keep for awhile and expand on.

 

...This paragraph removed by moderator...

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Doug,

 

I was referring to a larger softbox or scrim. You don't use umbrellas to light this type of subject because the specular reflections they create are shaped like umbrellas and are unattractive. What size and type of modifier are you using now?

 

Alien Bees are very popular with people here on Photo Net. They are very inexpensive and they are fine for starting especially if you are shooting people.

 

Shooting these large products you'll probably want more power and versatility. Look at ProFoto, Speedotron etc. pack and head systems. A couple of 2400ws packs and 4 heads, as mentioned earlier would be a good place to start.

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I'm currently using hot lights with umbrellas. I rented strobes for one day to get a sense of how they work because I'm evaluating whether to upgrade the hot light system or go with a new strobe system (the picture above was with the rented strobes and umbrellas). With the hot lights, I've been using hand-held diffusers, but as you noted, with larger pieces like in the photo, this doesn't work all that well. Regardless of the system I decide to go with (hot lights vs. strobe) I had planned to purchase softboxes to go with them. I hadn't considered scrims based on space constraints in my very small studio. What are your thoughts on softboxes vs. scrim?
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Doug,

 

I use flash, Speedotron 4800ws, 2400ws and 800ws power packs and 102, 202, 106 and 206 heads. Softboxes, scrims, grid spots, optical spot and fresnel spot are the modifiers that I use most.

 

On the occasional architectural interior job I'll use tungsten lights if there are no windows, daylight or fluorescent lights involved. That's rarely the case since there's usually a window in the shot or contributing daylight to the scene so I usually use flash for those shoots too.

 

In the studio, tungsten light is too hot and too dim for the work I do. I don't know if you've ever priced softboxes for tungsten lights but they are much much more expensive than those for flash. Flash is also more consistent for color temperature and easily adjusted for low and high light levels.

 

Most product photographers and most commercial photographers for that matter use flash instead of hot lights.

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Brooks - thanks again for the reponse. For Speedotron systems, I found a 2400 ws system online for sale, but I think it could be almost 10 years old, or more. Is it worth getting this older pack, which apparently works fine, or to invest in something newer? Would one 2400 ws pack be enough light for my very small studio, or would I really need two? Can you mix packs - e.g. one 2400 ws and one 800ws?
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Doug, next tie you rent the stobes, rent a meter and you will understand who easy it is with one. Fire the strobes, read the meter and set that on your camera. Very easy.

 

I have 4 Alien Bees (1600, two 800s and a 400). The kits are a bit spendy, you can get better and cheaper light stands on Ebay or at BH. If you buy an 800 and decide you need more power you can send it back and upgrade it for the price difference.

 

I had 3 cheaper Stellar interfit 300s and they weren't the most reliable, I think I sent at least 3 back. The Alien Bees are a great bang for the buck.

 

Mark

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