Question on shooting Macro video of foraminifera

Hi folks,

I recieved this email and I'm counting on the wonderful world of Wetpixel to help this young lady. Her question follows;

I have a question about macro filming with a 7d. I have never done any macro filming before so I am looking for some advice.

I am looking to do underwater macro video. I would be putting together a little aquarium set up for a controlled environment. The aquarium is 2ft. wide x 4ft. long x18 inches deep and black. The subject is foraminifera...single celled organisms about 3mm in size, ranging up to the size of your finger tip that live on the seafloor. I am not sure what lens and diopter combination would be best for filming this subject. Do you have any advice? I am a student so I am trying to do this as economically as possible. I have been looking into buying an underwater housing, but have also considered just trying to find a clear aquarium, grabbing a polarizer and seeing if I can film through the glass and cut the glare, as it would be a much cheaper option.

My third option, which I am not even sure if it is one, is to use my school's amphibico housing and V1U camera. I am not sure if there is enough room to put a diopter on the lens of the V1U inside the housing however and have not had any success in hearing back from amphibico about this (I hear they are going out of business so that may be why). The strongest diopter my school has that fits the V1U is a +4. I am not sure if this would magnify my subject enough.

I would very much appreciate any thoughts you have about this.

Thanks so much,

Hilary

Lots of options here, what would you folks recommend? I'll send Hilary the link so you can answer directly to her.

Cheers,

Steve

Hi Hilary,

Well I probably can't answer all the questions, but I have a few suggestions, and am familiar with foramenifera, being a marine biologist specializing in infauna.

I think the aquarium idea and 7D (or a video camera) is the best bet- the more controlled you can make it the better. If you're filming through the glass, lighting is key- if you can light the inside of the aquarium with some very bright lights, and have it dimmer outside you should be able to avoid reflections. A polarizer shouldn't be necessary and will cut down your light too much. It's sometimes helpful to make a hood too from the lens to the glass of the aquarium if you're having problems with reflections.

The problem with macro and the 7D is you will have a very shallow depth of field. You could try a 60mm macro with some dioptres and/or extension rings, but the DOF will be narrow. For this reason you might have more success with a camcorder, but you will need more light than the 7D would require, but a few very powerful desk lamps pointed into the aquarium may do the trick.

The other issue will be camera stability with a subject this small you'll want a tripod or some form of support whichever system you go for.

Good luck- should be a fun project!

Fergus

I would suggest trying to get your hands on John Shaw's 1987 book - Closeups in Nature. I've just seen it secondhand on Amazon £2.69 here in the UK. He has many options but using his directions for stacked lenses P112 should give you the workable high magnifications you are looking for using an aquarium and the 7d. You will need a reversing ring to link the lenses, and perhaps a step up ring for one of the lenses if they do not have the same filter sizes.

The magnification obtained is 1000mm divided by the focal length of the front reversed lens. So a 50mm stacked on a 100mm lens will give you 1000/50 or a 20x magnification.

I would also look at using the smallest aquariums available for the filming and use the larger aquarium as a keep tank. Try creating a small aquarium with microscope slides sealed with silicon at the edges, and a moveable slide inside to confine the object being filmed. A watch glass suspended on a ring of plasticine / modelling clay will also allow you a shallow depth for the specimen and the ability to light from behind as well.

Black velvet suspended in front of the aquarium with a hole to shoot through will also cut down on reflections. Camera on a tripod, and the aquarium on the heaviest table /surface you can find. I remember reading somewhere that Oxford Scientific Films had special granite tables built for their super macro filming.

Cheers

Rob

Thanks for the thoughts guys. This just got a little more interesting. A note from Hillary;

The shoot is in Antarctica so I need to figure out my gear soon. I leave Sept. 30th. This was sort of an after thought, which is why it has turned last minute. I am going to be doing some short podcasts while on the Ice about the research project. The PI has a lot of microscope footage of the critters, but we thought it would be fun to try and get some macro shots of them in an environment closer to their "natural habitat".

I appreciate your help!

Hillary