Some technical help for a university project

[722Adam]

For my final year project I'm looking into water droplet behaviour on vehicle surfaces, specifically measuring contact angles from images of droplets. The measuring will all be done automatically in MATLAB but for this to work, I require an image with a razor sharp droplet profile edge.

This is what I'm working with at the moment.



Essentially, MATLAB struggles to trace the droplet boundary, so I need it to be as sharp as possible in the raw image. I've had a play today working out which aperture my current lens works best at, using mirror lock up etc. and I already use a tripod and remote shutter, but my supervisor likes the idea of getting the droplet to fill more of the image.

The image was shot with a Canon 18-55mm IS kit lens, set at 55mm and positioned as close as it will focus (250mm IIRC), so by my understanding I can't get the droplet to fill more of the image with this lens. I possess an 80-210mm but with a minimum focus distance of 1.5m, by my reckoning it won't be any better.

Does this mean I need a new lens?

Been looking at these two, as they both quote 1.0x magnification:
Canon EF-S 60mm f2.8 Macro USM
Canon EF 100mm f2.8 Macro USM

Anything I bought would be attached to a Canon 550D.

Am I on the right track by thinking these will help me do what I want? (i.e. be able to stand close up and get an image with a nice big droplet in it)

Any other tips greatly welcomed.

[722Adam]

Thank you all for your suggestions so far, didn't think this would attract as much interest so I've got a lot to go on!

DavidY, at this stage of the project I think it is a little too late to go down a different route to DSLR, plus I am building off the back of a project from last year which started out that way, so makes sense to continue. I will however mention these other methods to my supervisor, as it may be a possible avenue to explore next year if it is considered at the start of the project.

I'm meeting my supervisor in half an hour or so, I'll discuss the options regarding lenses and extension tubes, see what the scope is for getting equipment in, if it's not hideously expensive, they could be convinced to buy it.

[722Adam]

Little update for you all.

Over the past week I've borrowed a macro lens from the design and print services studio. Being a Nikon lens I had to utilise my departments D3200 to try it out on, but I think it's going to give me what I want. So I've bought an adapter to fit the lens to my Canon body and tried that out, works a treat! Will be getting the images for my project next week as I have the facilities and equipment booked out (don't think I mentioned but I'm doing all this using UV light as it makes removing the noise from the image much easier).

I've also got the MATLAB side of things working so it's really coming together, actually feel like proper progress is finally happening

[722Adam]

It's a 60mm f2.8, not the newest lens but the guys I borrowed it from can't remember the last time it was used, as they don't do a lot of macro photography. All my canon lenses are a plastic construction so this thing feels bulletproof to hold compared to them!