Extension tubes!

I have just moved into the world of Macro photography and wondered if someone could explain in plain easy to understand language the effect extension tubes have on a lens and subsequent shot!,,,,thanks,,,,Ken

They move the lens further away from the film plane or digital sensor, and this has the effect of allowing the lens to focus on objects that are close.

It's more convenient to buy a proper macro lens, but if you aren't sure if you want to pay for one, this is a cheaper alternative.

G

Thank you George,,,I have just bought a Tamron 90mm,,which is giving me some reasonable results,would tubes allow me to get even better magnification?,,,sorry to sound so stupid but we all have to learn somehow!..lol///////////////////////Ken

Yes indeed, though for the highest magnification you need to buy a 200mm macro.

But first sell the house.

G

"Thanks George"....lol////////////////////////////////Ken

I have the Tamron 90mm macro (not the 1:1 unfortunately) and often use a set of Jessops tubes to get closer, the only problem with extension tubes is the shallow depth of focus (I hope thats the right terminology)...or is it field of focus???

Extension tubes can be fiddly but you will get some superb shots once you get aquainted with them, but bear in mind that as you are magnifying the image you will also be magnifying camera shake, which means shooting when there is plenty of light as your tubes will also reduce the effective maximum aperture of the lens.

For accurate focusing and controlling the depth of field, it is worth investing on a focussing rail (e.g. http://cgi.ebay.com/Macro-Shot-Focusing-4-way-Rail-Truck-4-Canon-Nikon-Fuji_W0QQitemZ320049644754QQihZ011QQcategoryZ30070QQrdZ1QQssPageNameZWD7VQQcmdZViewItem which you can attach to a tripod. The wheels allow you very fine control of the position of the camera. However most bugs move too quickly, so using a rail is only useful for static objects.
e.g.
http://www.ammonyte.plus.com/galleries/extensiontubes/slides/pound%20coin.html

In the example above, the coin is slightly angled as I didn't have a way of getting it square on to the lens, and you can see the effect of the shallow depth of field.

A Pentax Bellows works well too and incorporates back and forth micro adjustment but not side to side.

Downside is you need a cable release to stop down the lens unless you use it manually or wide open and another cable release for the camera. The double cable release that comes with the bellows is best left in the drawer unless you are using a film camera. Any attached lens will require the camera to be used in manual and stopped down metering. A ringflash is a good investment too. The more light you can throw on to your subject means you can use a smaller aperture with increased DOF.

Secondly, if you go the bellows route on a Pentax DSLR, get a short manual extension tube to fit between bellows and camera to avoid having to take the body mount of of the bellows unit before fitting it to the camera. The bellows will foul the camera body otherwise. There is no point in getting a KA tube because the contacts do nothing. If you already have some of course, use one of them, probably the shortest will do.

If you want to use a micro adjuster other than a bellows unit, Manfrotto make one and Novoflex units are frequently available at reasonable prices. Both excellently engineered products.

On film, luck plays a big part in determining the quality of the resultant shot. Spending ages setting up your gear perfectly counts for nought if your subject is unwilling/restless. With digital, you just keep clicking away until you get a few good ones and bin the duffers. I think digital SLR's are largely responsible for a bit of a renaissance of macro photography because 1 shot or 50,the cost is the same.

I'd like to see Pentax produce a KA Bellows unit one day. With modern flexible printed circuit techniques it ought to be possible to get the contacts from front to back. AF is not particularly necessary either.

Good luck,

Insight from a newbie...

I have a Pentax 1 bellows as well as a set of Haminex "auto" tubes. I've tried all the various combinations I can think of with 28, 50 and 135mm lenses (don't have a Pentax 200mm unfortunately), and I seem to wind up with the 135mm most often.
The beauty of the longer lenses in Macro, is that you don't have to be on top of your subject - thereby retaining perspective. It also seems that there is a bit more DOF.
Another advantage of using the longer lens(es) is that you can use your big sturdy tripod off the edge of the table instead of the tiny, tippy table-top tripods close up.
I've had no luck with my 50mm f4 Macro lens extended by tubes or bellows - not a good match - but wonderful on its own! Especially in the field.

If you use floods and an 80B filter as I do, I find a cable release invaluable as I'm often into time exposure to allow a smaller opening for increased DOF and to compensate for the 2 stop light loss created by the blue filter.

Now, anyone got a trick for me with the following problem?

I mostly shoot with a matt black background, and my Spotmatics' light meter needles become invisible when I stop-down below say f 5.6. I've resorted to holding a white piece of paper in the extreme right of the frame during composure, but fear this may falsely influence the reading. Are the meters center weighted so that this really isn't a problem?

Thank's

Hi Mac,

I wouldn't think the white card at the edge of the viewfinder would have a huge effect on the exposure reading. If you're really worried that it is, try this:

With your current piece of white card in place so that you can see the needle, introduce another piece of white card on the left hand side of the viewfinder, and see if that makes a difference. If it doesn't, it's fairly safe to say your original bit doesn't either. If it does, you can see by how much, and take that into account when using the piece you're using now!

Make sense? If not, let me know, and I'll try to explain it better. Perhaps with pictures!

Talking of pictures, and refering to your experiences with different lenses and extension tubes, I've found my 50mm f/1.7 to be good with tubes, but have also had fun with a 24mm and one (the 12mm) tube. Anything thicker means you can't focus at all. I like this combination as you still get a wide angle view, and exaggerated perspective, but obviously with close up ability. Example with toadstools below. These were about 1 inch high, and the front of the lens about 1 inch from the closest toadstool.



istD, Sigma 24mm, f/16(?), 12mm extension tube, Uniloc tripod, polariser!

Just got me some KA extension tubes so I'll be able to play with my 16-45, although my trials with my old tubes show that you can't get far enough away to focus on focal lengths shorter than around 24mm, but it'll at least give me the option of using it.

Dan

Thank's for the tip, Dan - will give it a go - shoulda thunk of it myself!

I always enjoy your forest floor macro work! Wouldn't a waist level viewer work a treat?

Cheers

I've got a rightangle viewfinder somewhere, got it off ebay a couple of years back, but found I never really used it much, prefering to get down on my knees and get hair full of leaves.

Just dug it out of the dreaded 'box of old, but potentially useful, stuff', kept under the bed. Ended up raking through the whole box, holding cameras I haven't touched for years. Praktica MTL5 - with its distinctive 'ker-chunk' shutter, Chinon CE5 - still feels so comfortable with it's power winder; I was using it, in preference to my MZ-5n, right up until I went digital. Lubitel 2! 6x6 Velvia slides!!

Anyway, found out the eyepiece adaptor on the R/A finder doesn't fit my istD, so still won't be using it.

Box now back under the bed, best get back to work.

Dan

Hi Mac,

re: the table top tripods, reminded me of a thread I posted back at the beginning of the year..

https://www.pentaxuser.com/forum/viewtopic.php?t=2118

As we've gained a lot more membership since then I thought it might be worth another showing..

Cheers

Liam

Just thought I might mention, to the "Macro Newbies", you don't need to rush out and buy the latest 'hot' kit to give macro photography a try. I bought a second hand 100mm f4 screw fit Pentax Macro lens about 25 years ago for my Spotmatic, and believe it or not I can still use it on my "brand new'" DS, so 10 out of ten to Pentax. I know ebay is 'the latest thing', but last year I got some extension tubes and a bellows, all screw fit, at a car boot sale in Ingliston Sunday Market, Edinburgh for £3.50, the guy originally wanted £12.00, so I think I got a good deal. The other cheap try-out, is to mount your camera lens backwards on to another lens that is fitted to your camera, you can get adaptor rings for this that will only cost a few pounds. The picutres below show an old tattie, ( potato ), that started to sprout shoots. The first is taken with the 18-55mm kit lens, the next with the 100mm screw Pentax macro, then the last with my £3.50 'super' extension kit + the 100mm Macro. Ok, I will admit it took me about 5 or 6 tries to get the exposure right, but I was well pleased with results. The kit is still being adapted, and I want to try some field use, but as development continues, I have a little change left for a wee bottle of 12 year old Dalmore malt. I think if I can join 25 meters of extension tubes together, I should be able to pick out individual atoms, allowing, of-course, for the Heisenberg uncertainty principle in quantum physics. Thinks . . . . . ( I could sellotape toilet rolls together for the same result ... ??? ) No, John that's the Dalmore taking !!!

That's the benefit of digital. Excellent demonstration, thanks.