[Franca]

Hi there fellow pentax enthusiasts - i have been combing through these forums looking for tips and have already found much great advice and info, but I am hoping if anyone out there has faced similar challenges they might be able to point me in the right direction.

I am shooting product shots on a white background (I will begrudgingly post these ugly images if it will be helpful) with a K-R.
Bright Natural light - in a room about 10 feet deep with southern exposure, no direct sunlight, mid-day....but bright, indirect natural light.
Manual setting, using the light meter to set the exposure - I think it was something like 1/50 for shutter, 5.6 for the aperture and the ISO was set to 200. Using a Tripod. I manually set the white balance, and am using the standard lens that came with the camera. I am bracketing.

I am really having a hard time with the exposure - it only seems to be a problem with the products on a white background and so I am thinking it must be that it has to be the way the sensor is reading the image and that I am not metering it properly. The brightness histogram generally has two huge spikes in the middle and the images themselves have this strange combo of looking either over exposed or underexposed and flat or both in the same image.

I switched from setting the sensor to a multi point reading to a central reading - but should I be spot metering? Should I lock the exposure? In which case should I set the exposure on the product or the background? If anyone has any advice it would be greatly appreciated!

[Not a Number]

Try spot metering on the object or a grey card or using an incident meter.

[Tanzer]

And you specifically don't want multi-segement metering, given the white background.

[enoeske]

If you are using all natural light, then by the time you get the background actually white, exposure-wise, your product will also have portions that are white, i.e. over exposed. You need to light the object and background separately, or understand that you have to get the subject looking good and make the background white in post production. I use the pen tool to clip out my products so the background is pure white.

So, get the product right, and take care of the background later.

white on white, black on white

[KGH]

I have shot portraits on white before. I have found you need to light the background separately for two reasons: you have to have a separation between the subject and the background, and you need to eliminate shadows by lighting behind the subject. I used a light that was about 3/4 stop brighter for white background than the main light. Anything brighter and you might get a washed out flare across the photo.

[Lowell Goudge]

Lighting the background, and spot metering off the product, combined sounds like a good solution. Spot metering is a necessity, for sure, but if your subject is white, as is the background, then metering off the subject will turn everything grey. So light the background to separate the subject from background, and then raise the level of the subject in post processing, which makes the background totally disappear into white. BUT be careful, white backgrounds or shooting dark against white especially can result in a lot of purple fringing

[Franca]

Thanks for all the replies everyone - I really appreciate it.....I am a little unsure though about what you mean by lighting the subject versus lighting the background...do you mean take a reading for the exposure of the background and the product separately?

[maxk7dish]

He means (I think) use another light source in addition to the natural lighting. Personally, I agree with enoeske that the easiest method is to properly expose the product, not worry about the background, and then mask the background out in Photoshop. The more contrast there is between your product and the background it is set against the easier the masking job will be. If you optimize this, you can get a clean mask using Channels much faster than you could draw one with the Pen tool (depending on how complex the shape of your product is).

[adwb]

Two lights minimum one for the back ground set 1 or more stops brighter then expose for the product light