Help using macro extension tube

[Kat]

Hi, I just purchased a set of macro extension tubes for an assignment I have for uni, I have never used these before and I am sure they work fine but perhaps it is me with the problem.

So I have attached the tube, first all of them, now just one and both times I have just blur through my lens, I understand you have to focus manually but should I at least be seeing part of the object I am photographing?

What am I doing wrong?

Can someone please help?

Kat

[MarkChap]

I would hazard a guess that you are much too far away from your subject

The idea of macro extension tubes to is to reduce the minimum focus distance thus giving a larger magnification.

What lens are you using ??

I would guess that with all 3 tubes on you are going to need to be with in about 50mm or closer to your subject

[Kat]

I should mention the gear I am working with

Canon 50d

Canon 17-85mm lens

Cheap and nasty extension tube set off ebay (broke uni student):(

[Kat]

Thanks Mark, I have tried moving closer and further away from my subject but nothing changes the blur through the lens, I am shooting a still life scene and it is about 20cm from my camera

[MarkChap]

Ok set the lens at 85mm and with all 3 tubes, you are going to have to be close as this lens focuses down to about 350mm on it's own, so get in real close with all 3 tubes attached, I would add just one at a time starting with the smallest and work up from there so you get a feel for the distance required.

If theses are the real cheapies from ebay, do they have the contacts for the lens and camera, if not you are not going to be able to close your aperture down and there fore will end up with a depth of field that is way too shallow and pretty much unusable.

[MarkChap]

Kat 20cm in way TOO far away, you need to be about 2 cm away

[Kat]

Thanks so much Mark, I just got it to work, they are the really cheap ones so I knew I had to manually focus but your explanation got me work it out, not exactly the best result but at least I will have images for my class next week. Should have just forked out the extra $40 to hire a decent lens for the day.

Thanks again

[dbax]

Kat 20cm in way TOO far away, you need to be about 2 cm away

with the 3 tubes on 2cm or closer.

Edit, and your Depth of field will be tiny

[balwoges]

Have you set your lens to manual focus? and yes, you just about have to sit on your subject :)

[Kat]

thanks for the tips, I was way too far away, I have one ring on now and it works fine, on my way to producing image 1 of 12 for my folio!

[dbax]

well done Kat, its a learning curve. If you get stuck this is the place to ask advice:D:th3:

[wazonthehill]

Yeap they are interesting to use with a normal (none macro) lense.
I was trying to focus a tiny flower an tried to focus on the back petal. Realised the trouble was that I was hitting the flower and pushing it "away" as i tried to move the camera forward!

[clm738]

Kat can you post some pics taken with the tubes as I am very interested in the results.

[balwoges]

Hope I am not hijacking this thread, however, was experimenting with my Canon 60mm lens and Canon Extension Tube 25 11 this morning, below is one of the results. Actual leaves 2cm long and you can hardly see the baby shoots with the naked eye.

[Kat]

Here a few from today, I couldn't get them really sharp no matter what I tried, so 5 hours later I finally have 6 of 12 images I need, will keep practicing with the lighting and extension tubes.

Gear used today

Canon 50d
Canon 17-85, F4-5.6
Cheap and nasty extender tubes
Cheap and nasty Bunnings work lights

Result (only quick PS work here)
42722

42720

42721

[accesser]

That last one is cool Kat :th3:

[Tricky]

Ha ha, yes the last one is a cracker! :D

[peterb666]

Stop down most of the way. Probably f/16 and take a long exposure. P.S. Make sure you focus with the aperture opened up as wide as it goes first. I did like that last series and I hope the Lego guy put out the fire before his extinguisher melted.