photographing blood products

[gregory_barta]

I am going to photograph blood products at work such as bags of

packed red blood cells and bags of plasma. I am going to try and

document the difference between normal and possibly abnormal

characteristics. Basically they are not giving me any budget for

equipment, I have to use what I have or can afford getting. I

currently have a Nikon N80, Nikon 24-85 f/3.5-4.5G IF, SB80DX

speedlight. I plan on getting the attachement cord so I can remove

the flash from the camera. I probably don't have the money to buy a

new macro lense. I don't have a lot of time to figure this all out.

I have a couple weeks before I have to start taking photos to have

them done by the end of October.

 

I took a few shots on the end of a roll with the flash on the camera

at a foot or so away. The objects are in focus but there is a white

haze on the part of the surface of the bags. I'm not sure if this is

do to some sort of reflection or what. I'm thinking getting the

flash off the camera may help. The size of the bags , I'm guessing,

are around 12cm X 15cm or so.

 

My curreent plan, after I get the cord for the speed light, is to

hold the camera in my hand and have someone else hold the flash to

the side of the blood product aimed downward at a 45 degree angle.

The blood product bag will be flat on a counter with the camera held

looking down on top of the object. I will use the camera's internal

meter for setting the exposure. Would I benefit from a gray card in

this situation or shoud I just expose directly looking down on the

object? The object will take up most of the visual field.

 

It seems based on the SB80DX distance message I should only be as

close as 2 meters when I have the lense set on 85mm. Can I ignore

this distance range that shows up on the speedlight and shoot closer,

like around 12 inches so I can have a good closeup shot showing good

detail? I know the lense will focus this close from the object.

 

Any suggestions about the use of a gray card, the shooting distance,

or any thing else that might help me in my task would be appreciated.

[conrad_hoffman]

I'm not a doctor, some would say I'm not a photographer, nor do I play either on TV, but- it seems the only abnormality you'll be able to detect is a color change, thus perfectly consistant lighting and exposure is called for. I'd use the gray card. Now might also be the time to spring for that flash meter you've always wanted. I'd also make or buy some type of diffuser, umbrella, or softbox for the flash. Harsh lighting probably won't serve your purpose. Processing will wreak havoc on consistancy if you use print film and a less than stellar lab. Maybe transparancies would be better? If you use print film, be sure to shoot a couple frames of a color control chart at the beginning of each roll, using the exact same lighting as the subjects. Hopefully, the lab can use that and keep the settings constant for the rest of the roll.

[Jerry_]

Have you considered explaining you do not have the equipment to do the job? The 'owners' of the blood cannot be that broke that they do not have the $$$$s to hire someone for their 'production' photo shoot.

[h._p.]

If I were doing this, I'd not use flash. I'd use daylight from a window and a tripod. That way, you'll have the best chance of showing the colour change you're looking at. More important than anything else will be a comparison object, presumably a 'good' bag or some form of colour swatch.

 

This is a good example of where slide film comes into its own - you don't want a computerised printer 'correcting' the colours. My approach would be to bracket each shot on the first film one and half a stop both up and down (five shots in all) and get the film processed by a reliable lab. For subsequent films you can, with any luck, set your meter accordingly and just get on with it.

 

The downside of using daylight, especially in the winter, is that there will be a limited time when you can do the work - colour temperature shifts quite a lot at that time of the year.

[david_clark10]

Yes I would go for daylight to. Or alternatively bounce the flash (off a low white ceiling or piece or card) to try to soften the light. Using harsh flash straight onto the bags will mean that it will be hard to see anything inside past the harsh reflections of the flash. If you are getting an off camera flash cord, then take the flash to one side and bounce it - otherwise either way you will be too close. The reason the flash has a minimum distance is because - it is quite high on the camera so the closer you get to the subject the less area the flash will cover. Normally you would use a ring flash for this type of situation. I don't really understand the set up as normally this would be done in a lab environment in dishes (the bags make it near impossible to avoid the reflections you are getting) with a macro lens and ring flash this way any abnormalities would be clearly seen. With this work slide film is always used to keep colours constant. Good luck

[Ed_Ingold]

The SB-80 may be a little hot for closeups. You can cut down the intensity by using the wide-angle adapter, along with the diffusion dome. I haven't had any problems using the SB-80 for flash fill in macro work, since I usually stop down to f/16-22.

 

Exposure is not the main problem. You want a uniform light source, free from shadows. The 45 deg flash angle won't do that. On the cheap, get a couple of pieces of white foam-core board: one for the backdrop and one as a target for bouncing the flash. The milkiness you mention is probably due to reflections. Diffusing the flash by bouncing it should be help.

 

You will absolutely need a tripod. The depth of field is small and the the effects of camera motion are amplified when working close. It's really difficult to parallel, frame and focus by hand

 

If you can't get close enough with your lens, use a closeup lens like the Nikon 3T, 4T, 5T or 6T if one fits your camera. They have an achromatic element, and work well with zoom lenses.

[Edwin Barkdoll]

I would consider shooting with tungsten lamps using crossed polarizers to

eliminate much of the glare - two light sources would be dirt cheap and you

probably already have a polarizer for your lens and sheet polarizing material

is available online thru a variety of places in sizes easily large enough to

cover the tungsten lamps.

[michael_briggs2]

I suggest creating a setup so that the camera, lights or flash and object are always located in the same positions. You could even make a simple setup from scraps of wood and a 1/4-20 screw to hold the camera, and some clamp to hold the flash. Do some test exposures with bracketing to find out which exposure gives the best results. Thereafter use the same exposure for all of your photographs. You don't want the meter giving a different exposure to light and dark products, so everything should be set to manual rather than automatic operation. I am not familar with the Nikon products you mention, so I don't know whether this is possible. If you use one light source, a white card would be useful to fill in the shadows and even out the lighting.

 

 

I suggest including a color chart and grey scale in every photo. Be sure that the chart and scale receive the same lighting as the product. These will give a color control so that when you compare two photos of two packages that show different colors in the packages you can know that the color difference is real and not due to some variation in the film, or in your procedure or in the process of making prints (assuming that you have prints made). A good choice for small size and low cost is the Kodak Color Separation Guide and Gray Scale (Q13, small). If you have a professional lab make prints, you can instruct them to make the gray scales neutral and identical in all the prints. Automatic printing machines may do strange things when most of the photo is one color and you might not get accurate color reproduction.

[lex_jenkins]

I dislike being a naysayer - my usual role is to encourage folks to try something rather than to discourage them. But in this case I'm inclined to agree with Gerald.

 

First of all, I don't understand the premise of the project. I've worked in the health care field and can't think of any valid conclusions that could be reached by looking at or photographing blood products, other than "It's red" or "It's clotted" or "Somebody needs to fix the centrifuge."

 

Also, you don't have the equipment or expertise to do the job. It's that simple.

 

What you really need to do the job properly is some studio lighting with modeling lights to let you preview the setups. You need a flashmeter. You can rent these things but you'll need a budget for that. And time to master the equipment.

 

OTOH, if the project isn't critical and neither the "client" nor you will suffer any harm (to finances, reputations, etc.) as a consequence of failure, and they're willing to allow you the liberty to approach this as an experiment or learning process, well, by all means have at it.

[klix]

Sounds like product photography specifically for Biomed products -- so all the techniques for product photography apply.

 

Obtain a product photography lighting systems, like the ones found at

http://www.mkdigitaldirect.com/

[gregory_barta]

I would like to thank those of you that responded with suggestions and helpful information. It is appreciated. This is for a revision of a Visual Inspection Reference Guide for different types of blood products showing normal and abnormal conditions that are possible. If I figure this out in time and get some good shots I will submit them, otherwise it will be a good learning process and I'll be ready for the next time photos submissions are requested from the different regions.

 

I do believe it would be hard to have consistent conditions using natural daylight. I like the idea of artificial light, such as tungsten that was suggested. I bought a couple clamp lights at the local building supply and a couple tungsten bulbs at the camera store. The local camera store person suggested I use Ektachrome tungsten slide film. I got a roll of 160T. Will the tungsten light source with the tungsten slide film allow for realistic color results such as might be possible using natural daylight?

 

I also purchased a Tiffin circular polarizer filter for my lens to help prevent glare/reflections. The camera store person said to rotate the filter while looking through the camera till the desired results are seen.

 

the camera store person suggested I dont't use the flash with the tungsten lighting/ tungsten film since it would be mixing 2 different light types/sources. Any comments about this? Would the flash be unnecessary with the tungsten lights or could the flash enhance them?

 

thanks again to everyone for their input.

 

gregory barta

[conrad_hoffman]

Your camera store sounds pretty good. If you got the right color temperature photo bulbs to match the film, the color rendition should be good. Don't mix in flash, as it will be too blue. Turn off any other lights, expecially florescents, and keep daylight out! The polarizer may help, but remember that it will cost you two stops in intensity. Good luck!