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I was thinking the other day that I might like a longer focal length macro lens (mine is 35mm effective 70mm) so I don't have to get so close to the subject, and I can have a larger DoF. So I thought a teleconverter might be useful, which could also be handy for photographing birds and whatnot with my zoom.
However everyone seems to talk about extension tubes which would do a similar thing but for less money.
What do you reckon?
Teleconvertors and extension tubes are totally different.
A tele will extend your focal length and reduce the effective aperture.
A tube will magnify the image, give you extremely narrow DoF and draw in your front focal range dramatically, ie you'll be able to focus close but not far.
For anything at any distance, such as birds, a tube will render your camera useless. A tele will work but you're going to need plenty of light.
Extension tubes extend the back focus distance of the given lens, effectively allowing a closer point of focus (macro) without affecting the focal length (ie a 50mm stays at 50mm).
A teleconverter extends the focal length of the given lens, by whatever ratio the teleconverter is (typically 1.4 or 2.0) Ie a 200mm lens with a 1.4 converter becomes a 280mm lens.
The trade off with teleconverters is the same affect on the Aperture. ie an f4 lens with a 1.4 teleconverter effectively becomes an f5.6. Most TTL metering systems will automatically compensate but does require higher shutter / iso's if your pushing for light.
Other negative (damn there are a few !!!) is the loss in image quality, putting several lens elements in the light path will have some negative impact which differs from model to model as well as impact on Autofocus (which is body dependant depending on focus sensor type).
And lastly, when using teleconverters ensure their is sufficient room behind the back element of the lens to accommodate the teleconverter, or you will damage the elements !!!!
Given the focal multiplier you've given (35 to 70mm), I assume its on a 4/3rds system in which case choices are fairly limited, the other option is to use a lens adapter and go for a manual focus macro lens from another format. I've used several Leica and Canon lenses on a G1 and been pleased with the results.
Also, the longer the focal length, the shallower the depth of field for the equivalent magnification / subject size at the given aperture.
Yeah I know about the distance focusing thing.
Really what I want to know is how to maximise my DoF for macro shots and still get the zoom. Beyond using a smaller aperture of course.
I don't want to spend a lot of cash. Oly's own teleconverter is £300 which is pricey for me but would have a double benefit in allowing me mega zoom possibilities with my 300mm.
Rereading your question I suspect you may know what I just posted. Thought you were thinking if a tube for macros and birds. Lazy reading.
Yes, for close macro stuff a tube is better. You will have very thin DoF though.
You will have very thin DoF though
Hmm, this is the thing. It's already stupidly thin, like half the time I can't get the stamens and the petals both in focus.
Alternative suggestion: For DoF in macro shots a small sensor works better. Ricoh compacts focus to 1cm. You can puck them up for 30 notes on the bay.
Nikon (and others) also do a series of screw in macro / magnification filters, quality is acceptable but does allow non macro lenses to focus closer.
Other option is to introduce more light, and use a smaller aperture, there are several cheap(ish) ring flashes that would be suitable for macro photography.
I have already used an excellent Oly compact many times for macro. I suppose this is what I am trying to replicate.
I will probably get one of those ring lights (the flashes are way too expensive) but that would eliminate shadows I fear. I might just get a bright torch and hold that up 🙂