Product photography: Flash or continuous lighting?

[Electricblue73]

Hey everyone, I'm a newbie at photography in general. I just recently purchased some strobes (160ws) with capability to use model lighting (75w each).

I recently setup a small photo studio in one of the bedrooms because I am selling handbags and other travel bags for my website, so I am taking photos of them. I am currently using the model lights (3 light setup: 45 degree at front shining toward product and background, and one on top) with soft boxes, and white background roll paper.

The camera I have is a Canon T1i 500D with the canon 18-55m lens for the photos.
Before each session I am using an 18% gray card to set my WB.
I am also using a sekonic L-358 to get the ambient light reading for the modeling lights (in ambient mode). And then set my camera accordingly

As I am taking photos, I am looking at the histogram making sure that the high and low end of the color tones are not cut off.

The question I have is about the exposure setting on my camera.
1. when taking the gray card photo to set the WB, what exposure setting does it have to be on?? How do you know what the correct exposure is?

On the canon, I have it set to Manual mode so I can adjust the shutter speed and f stop accordingly.

2. When I set the camera to the same settings as the light meter, when I'm about to take the picture, I'm getting different exposure settings on my LCD. How come it is doing this?
How do I know what the correct exposure setting is suppose to be......lately I have been adjusting the shutter speed so that the exposure is +1 because the results in the histogram look the best, and then when I look at them on my computer, the background is fairly white (sometimes it is a light gray).
Sometimes when my camera is set to the light meter specs, the camera's exposure will be either on +2 or -1 or -2.........so I'm confused which exposure is correct.

What is the supposed to be the correct exposure, most of the time I have to adjust the shutter speed to get the exposure to +1 which looks the best both on histogram and on computer in the DPP canon software

My goal is to get a nice white background without editing, and of course the most accurate color and correct exposure.

The different exposure settings every time I take a photo is confusing me.......

3. Should I be using flash instead of continuous lighting for the products I'm photographing? So far, I'm getting pretty good results, but I don't know if my exposures are correct. I still have to do minor tweaks to contrast and maybe brightness or shadows, but thats about it. Not all the backgrounds are turning out white, some are a very light gray, but not worse than that. Histogram are showing that everything is close to 0 and 255 without any abrupt spiking or washing out at the limits

 

[Josh66]

1. when taking the gray card photo to set the WB, what exposure setting does it have to be on?? How do you know what the correct exposure is?

Look at the meter in your viewfinder. Zero that out.

2. When I set the camera to the same settings as the light meter, when I'm about to take the picture, I'm getting different exposure settings on my LCD. How come it is doing this?
How do I know what the correct exposure setting is suppose to be......lately I have been adjusting the shutter speed so that the exposure is +1 because the results in the histogram look the best, and then when I look at them on my computer, the background is fairly white (sometimes it is a light gray).
Sometimes when my camera is set to the light meter specs, the camera's exposure will be either on +2 or -1 or -2.........so I'm confused which exposure is correct.

What is the supposed to be the correct exposure, most of the time I have to adjust the shutter speed to get the exposure to +1 which looks the best both on histogram and on computer in the DPP canon software

My goal is to get a nice white background without editing, and of course the most accurate color and correct exposure.

The different exposure settings every time I take a photo is confusing me.......

Sounds like you're more or less doing it right. Use the settings your meter is giving you, and then overexpose by 1 or 2 stops to make the background white.

3. Should I be using flash instead of continuous lighting for the products I'm photographing?

Doesn't matter. The product isn't going anywhere and you're working from a tripod (I hope). Continuous lights are hotter, but other than that, there's nothing wrong with them. Unless you're working with a heat sensitive product...then a flash might be better.

 

[Big Mike]

Welcome to the forum.

For shooting a still subject like products, it's perfectly OK to use constant lights like the modeling lights on your strobes. It seems a silly way to go about it though, because you paid for strobes, the modeling lights are really meant as a visual aid, not really for shooting with.

1. when taking the gray card photo to set the WB, what exposure setting does it have to be on?? How do you know what the correct exposure is?

Grey cards are actually meant for setting exposure. Setting WB is a bonus.
When using the card, have the camera in manual mode and adjust the setting to centre the 'needle' when the card is in front of the camera. The needle will probably move when you take the card out, but that's OK because you have set the 'correct' exposure.

2. When I set the camera to the same settings as the light meter, when I'm about to take the picture, I'm getting different exposure settings on my LCD. How come it is doing this?
How do I know what the correct exposure setting is suppose to be......lately I have been adjusting the shutter speed so that the exposure is +1 because the results in the histogram look the best, and then when I look at them on my computer, the background is fairly white (sometimes it is a light gray).
Sometimes when my camera is set to the light meter specs, the camera's exposure will be either on +2 or -1 or -2.........so I'm confused which exposure is correct.

The camera's meter is always trying to make things the same tone as the grey card, 18% grey. So when you have a lot of bright areas in the scene (a white background for example) the camera's meter wants to turn that all to grey (underexposed). So the correct exposure might be one or two stops above the meter reading, that's why you're finding that it looks best at +1 etc. Because that is probably closer to correct.

The camera's meter is a reflected meter, thus it is influenced by the reflectivity of the subject (how bright or dark it is). This means that it can be fooled when the scene is brighter or darker than 18% grey. That's why we use a grey card.
Also, you could use your light meter, and meter the light that is falling on the scene. This is called an incident light reading. It measures the light without the reflectivity of the subject, so whatever the light meter says, is going to be much closer to accurate. That's the beauty of a hand held incident meter, you don't have to worry about figuring out the reflectivity of the subject.

3. Should I be using flash instead of continuous lighting for the products I'm photographing? So far, I'm getting pretty good results, but I don't know if my exposures are correct. I still have to do minor tweaks to contrast and maybe brightness or shadows, but thats about it. Not all the backgrounds are turning out white, some are a very light gray, but not worse than that. Histogram are showing that everything is close to 0 and 255 without any abrupt spiking or washing out at the limits

Well, that's a tough question. Strobes are in many ways, a superior light source...but they are also a bit more complicated, especially when you are trying to learn how this all works. The good news is that you do have a flash meter, so you have the tools to make it work. Just fire the strobes with the light meter and see what it says. Use that reading as your aperture value and you should be good to go. (shutter speed doens't affect flash exposure, just keep it under the sync speed of 1/200).
You may need something extra to trigger the strobes because you camera doesn't have a PC port...and using the built-in flash to trigger them, probably won't work because of the pre-flash.

Either way you go about it, you can probably use the histogram as your guide. Just remember that to have a nice white background, with a properly lit subject, you may need to have more light actually on the background, than on the subject.

Setting and using a custom WB is a good idea, but you can also shoot in RAW mode and adjust the WB afterward.

 

[Electricblue73]

3. Should I be using flash instead of continuous lighting for the products I'm photographing?

Doesn't matter. The product isn't going anywhere and you're working from a tripod (I hope). Continuous lights are hotter, but other than that, there's nothing wrong with them. Unless you're working with a heat sensitive product...then a flash might be better.[/QUOTE]


I actually tried using the flash and my photos are turning out a lot better. I used the light meter to set up the flashes, and then gray card to set WB. Flashes are less hot but I'm getting whiter backgrounds which is what I need from the start. I still have to adjust the exposure a little, but it seems like the normal thing to do, from what you said.

 

[Electricblue73]

You may need something extra to trigger the strobes because you camera doesn't have a PC port...and using the built-in flash to trigger them, probably won't work because of the pre-flash.

Either way you go about it, you can probably use the histogram as your guide. Just remember that to have a nice white background, with a properly lit subject, you may need to have more light actually on the background, than on the subject.

Setting and using a custom WB is a good idea, but you can also shoot in RAW mode and adjust the WB afterward.[/QUOTE]


I am using a pc shoe adapter on my canon and it is connected to my master flash and using a remote to trigger.....although I should probably invest in a wireless system.

I am also shooting in RAW mode so I can make adjustments if needed. I will try putting more light source on the background to get it white all the time. Sometimes, depending on the color of the product, the background comes out a very light gray but the product itself looks fine. So more light on the background probably is the solution.

Thanks for the tips!!