Extension Tubes - Give me your thoughts

[edneeves]

I currently have a D70s, 18-70 Kit Lens and a 70-210. I have a birthday coming up and was looking for fun (and not to pricey) additions to my kit.

I am really into doing some macro work and thought a set of extension rings would go down nicely.

Could those using them give me their thoughts?

Would they work with the above lenses (plus maybe a 50mm f1.8 depending on how generous my partner is feeling)?

How much stress is the Tube + 70-210 combo going to exert on my camera mount? Is this a good idea?

Makes and models would be appreciated.

Regards,

Ed.

[Matt. K]

Extension tubes have no internal optical elements. Because of that they will not degrade the optics you choose to use for your macro work. Be aware though that you will have to focus manually and your lightmeter will not work, so you will have to use your histogram to nail correct exposure. These are minor points and the tubes will allow you to capture macro images at a professional quality.

[edneeves]

Do you use any? If so which ones?

Ed.

[Matt. K]

I use the cheapest ones that will mate to Nikon lenses. I forget the brand but they cost around $120. Try and get them secondhand or on ebay and you might get them cheaper. Another option for you is to get a reversal ring for your 50mm lens. This too will give you excellent macro imagery and should cost about $50.00. Personally I'd go for the reversal ring.

[NikonUser]

The kenko set of tubes allow full autofocus and metering.

I own this set and they are fine to use. They aren't the best made products on the planet but they get the job done.

Paul

[NikonUser]

Does the 70-210 lens have a tripod foot? If so then there shouldn't be any problem with the strain on the lens mount. You just have to support the camera a little more carefully when you have a large amount of extension attached.

Also for macro have you considered the Canon 500D closeup diopter? They work quite well I have read and seen (but I have no experience with these myself on a DSLR).

Paul

[katweazl]

Hey edneeves,

I just bought a set off ebay....I am in the same position as you and just thought what the heck I'll get them.

They cost me just over $30 shipped. Don't know the build quality yet cos they haven't arrived but I thought for $30 I couldn't really loose.

I will be using my 50mm 1.4 with them. Was thinking about using a reversal ring with the extension tubes....dunno how that would go.

Anyway this is the link to the item I won.

Joel

[edneeves]

unfortunately the 70-210 doesn't have a tripod foot, plus its a pretty solid thing. Thats why I am a little concerned that adding x amount of mm onto the lens might cause horrific amounts of stress on the mount.

Nikonuser, when you say that the Kenko units aren't the best made what does this result in? I have heard that with a larger lens you can end up with some form of droop, is this true?

Ed.

[big pix]

have you had a look at a set of close up lens........ they will give you a good result....... without the manual hassel..........

[edneeves]

I was looking for a pretty cost effective answer that I could use across all my lenses. Plus I like to manual focus a lot of the time so this isn't really an issue for me.

[big pix]

I was looking for a pretty cost effective answer that I could use across all my lenses. Plus I like to manual focus a lot of the time so this isn't really an issue for me.

buy a set of close up lens to fit your largest lens and step down rings to fit your other lens....... very cheap

[katweazl]

Are the close-up lenses (more like filters) optically good? Will you notice a softening of the images?

Joel

[NikonUser]

I think that with a heavy lens you would have to be quite careful when holding the camera with a lot of extension with the Kenko tubes (or any for that matter). I definately wouldn't be confidant attaching all three of my tubes and then using the camera's tripod socket.

The Kenko tubes are made from plastic with metal mounts. They don't seem to fit together all that tightly. It's not really an issue (for me anyway) but there is definately quite a bit of twisting between the tubes. This hasn't ever caused any errors or anything.

As for the closeup lenses. There are two types. Single element and (the more expensive) double element. I've used both on my old Olympus P&S. The single element ones were definately very soft at the edges and suffered quite badly from CA... however the Double element canon 500D is very good.

Good luck with your choice

Paul

[edneeves]

Nikonuser,

Just read some science on the Canon 500D and am a little puzzled how such a small thing on the front of the camera (a la filter) can cause such compelling results.

This truely has thrown a spanner into the works. Is anyone else out there using one? Are there any downsides to the device?

Ed.

[marcotrov]

It is one i have considered and still am. The results, used properly, are impressive. Kerry Pierce, one of our members uses one and highly recommends it. It(canon 500D) is dual element filters hence the price and quality. Secondly, my understanding is that there is no light loss as opposed to extension tubes, then again unlike extension tubes your limited on what you can use it on because of thread size, unless you invest in stepdown rings and unlike stepdown rings you don't have to unmount your lens when you want macro, just screw it on and camera works just as it would without it. If you go through google and type closeup filters versus extension tubes and other such descriptors you shuld find information to satisfy you. I think on balance something like Kenko extension tube set will be cheaper depending on your filter thread size. Good luck with your decision.
cheers
marco

[Finch]

As a couple of others have said, extension tubes have no optics, therefore no loss of image quality. You will, however, lose some light. Close-up filters are a good second option, are fairly cheap and won't cause any stress on lens mount. Being glass, though, means there will be some loss of image quality.

Hope this helps

Cheers

Michael

[SteveGriffin]

I personally prefer extention tubes over diopters.

I have a Kenko set which still gives you AF & AE provided you don't stack 2 or more of the extentions.

You will find that you won't get much advantage when using them with longer focal length lenses however. I think that the best results I have had have been with 50/1.4 and 60/2.8 Macro lenses

Here is a link to some recent examples

[christiand]

I had a KENKO extension tube set on loan from a friend.

Loved it, so I finally ordered a set via Ebay.
Metering and focussing will still work: $AUD 189 incl shipping.
Focussing is better done manually if you want to control what is in focus.

Cheers,
CD

[SteveGriffin]

I agree with Christiand on the focusing. I generally mount the camera on a tripod and focus manually as that is the only really reliable way to get the focus to occur where you want it.

Can anyone explain the maths behind extention tubes in language that a high school dropout can understand??????

[edneeves]

2nd on the theory. I have just spent 45 minutes trying to re-find the equations but to no avail.

Ed.

[edneeves]

One other question I am trying to figure out:

What would deliver the most magnification, 50mm with extension or a 70-210 with extension. I understand that 68mm of extension on a 50mm lens would offer up a greater then 1:1 magnification but does the extra length of the 210 help at all. Also do the minimum focus distances of both lenses have any bearing on the final magnification?

Damn confusing subject!

Ed.

[NikonUser]

Here is my understanding (but could very probably be wrong)

to get 1:1 with a 50mm you need 50mm of extension

to get 1:1 with a 200mm you need 200mm of extension

So you would have much higher magnification with the 50mm. The advnatage of the 200mm would be working distance.

Paul

[edneeves]

Does that mean for a 50mm you would have 5 inches working distance and for a 200mm you would have 24 inches (I am making these numbers up).

Does this mean that if you use the 200mm at 2 inches you can get 1:1 + by using less that 62mm extension?

Ed.

[Bretski]

Interesting topic... I too want to foray into the world of macro and have been looking on ebay at the various extention tubes ... they vary from the elcheapo $30 range (manual everything) to a few hundred with all the AE AF hookup etc...

But I like the idea of screw on filter idea ... so now I have to research all again...

Seems to be a bit like the Holden/Ford Nissan/Toyota allegiances... Tubes/Diopler... Hmmmm ... Decisions Decisions....

[NikonUser]

Or you could get tubes and a diopter....

That's what I plan to do in the near future (got the tubes already)

Paul

[tasadam]

While on the subject, what would happen if you use extension tubes with a macro lens, say the Nikon 105 macro? Does it give you closer still or what?

[NikonUser]

Yes it does tasadam... I use extension tubes quite regularly with my Sigma 180 macro.

The shorter the focal length the more pronounced the effect will be with the tubes.

You have to be careful with diffraction making your images soft though.

Paul

[DionM]

Extension tubes get my vote.

I use them often with my 100mm macro, works well. I use aftermarket brand (Kenko).

I have not yet used them on other lenses, but they will work.

[Steffen]

to get 1:1 with a 50mm you need 50mm of extension

That doesn't sound right. From what I remember about optics, the subject distance is f(1 + 1/m) and the image distance (extension for all intents and purposes) is f(1 + m). Hence, at m=1, subject distance and extension are both 2f. For simple prime designs (that don't change their focal lens as you focus closer - like the 60 or the 85 do) the distance between subject and film plane can simply be set to 4f in order to achieve m=1 (1:1).

At infinity focus (m=0) the extension is f and the subject distance is, errr, infinity.

With tubes and no TTL metering you have to compensate for the light loss. I believe you have to multiply the f-stop by (1+m). With diopters, this isn't an issue.

(f being focal length and m magnification, of course)

Cheers
Steffen.