Macro Accessories - Extension tube vs Macro/Closeup Filters

[dcheung]

I'm wondering what would be better to get?

 

The closeup filters are definitely cheaper than the EF12 and EF25 extension tubes.

The extension tubes reduce amount of light coming in because u end up using only

the center of the lens so it reduces effective aperture.

Does the closeup filter also do this? or is the effective aperture maintained

since it uses the entire lens front element.

 

I've tried some closeup filters and they aren't too sharp. Lots of chromatic

aberrations. I'm guessing the extension tubes are better since it does not add

a piece of cheap glass.

 

Anwyays, I just want to know more about these accessories.

 

Thanks.

[bill_b2]

Closeup lenses do not reduce light.

 

2 element closeups, meant for telephotos, can be very high quality and are not cheap. A telephoto is often helpful, anyway, to give a good working distance. The working distance is from the front of the lens. The minimum focus distance is from the film or sensor plane in the camera body. A big difference with telephotos. The closeup manufacturer specs will tell you the minimum focal length lens they recommend for their products.

 

Quality closeups are very convenient, great for low light situations, and give good quality. They are not a substitute for a quality macro lens. The vice versa is true, too. Low light macro occurs more than you would think. Early morning dewy plants, butterflies, etc. When you are stopping down to counteract the very reduced depth of field, and trying to maintain a shutter speed that will freeze the action, and any motion is a big motion at macro distances, the ability to avoid sacrificing any light becomes very important.

[anupam]

Bill, closeup diopters DO reduce light as light loss is connected to magnification. It's better to think of it as light being spread out rather than lost. At the same magnification closeup diopters and tubes give the same shutter speed.

 

-A

[papasan]

Close up lenses/filters even of higher quality will introduce some distortion to your image. They are like magnifying glasses in front of your lens.

 

Extension tubes on the other hand do not have any glass element and therefore will not cause distortion or abberations. They work by moving the back element of the lens away from the film/sensor and hense through the law of optics reduce the minimum focus distance, allowing you to focus closer to your subject. The Canon EF12 and EF25 are fairly expensive and have to be procured separately (adding to the cost). You can get a set of Kenko tubes for a fraction of the cost of the Canon and they work fine with EF lenses. They come in sets of 3 and can be used in 7 different combination. They also maintain full electric connection between the lens and the camera. I got my set from Camera Canada for C$178 or so.

 

cheers

[bill_b2]

Anupam,

 

Sorry, but no light loss with closeup lenses. The loss that comes from magnification occurs because of the camera lens moving away from the sensor/film plane. That is why extension tubes reduce light and closeup lenses do not. No formula for it, but the real macro enthusiasts will probably post something to give the details.

[anupam]

Bill, it's called the inverse square law - light isn't lost with distance it's lost because it's spread out over a larger area. So it is tied to magnification. As for your claim - how about trying out the two setups to obtain the same magnification and then comparing the shutter speeds. I have, after I made the same erroneous claim and Bjorn Rorslett corrected me on this forum.

 

-Anupam

[anupam]

<a href=http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00H0UY>Here is the thread</a> I am referring to with Bjorn's post and my correction of the mistaken claim. <p>

-A

[tommyinca]

Close up filters come in real handy (and works well) with longer focal length lens. For example: you will need 100mm (a lot) of extension ring on a 200mm lens to get near 1:2. A +2 close up lens (e.g.: 500D) will get you pass 1:2 on the same 200mm lens. A good dual element close uf lens should not add too much CA. Get something like the Canon 500D or Nikon 5T,6T.

[cromwell1664877587]

Anupam, you might want to add that when people do this test, they keep in mind the dof with the tubes is going to be greater than what they're used to the camera saying it should be. Example: Lay a receipt on the table with a flashlight laying down shining on it. The flashlight is because you have to get closer with the dioptors and you don't want the ambient light you're blocking to have any affect. Fill the frame with a word using 2 250Ds stacked on the end of your lens. Your camera may read f8 at 1/60. Take the same shot with a set of extension tubes and your camera may read f8 at 1/20. When you look at the pictures, the shot with the tubes has a much greater dof, so when you compensate by opening up the aperture to have the same dof as the shot using the dioptors, the shutter speed should be about the same. As far as answering your question, Weiyang, a set of Kenko extension tubes are cheaper and will probably give you a little higher quality picture.

[peter_foiles2]

Michael-

"Extension tubes on the other hand do not have any glass element and therefore will not cause distortion or abberations."

 

Not really, lens designs are optimized for a given lens to film plane distance. When you change that distance with an extension tube yo loose optical quality.

[cromwell1664877587]

The more I think I about, the more I'm sure I was at least partially wrong in my last comment. I've done very little macro shooting this year, but thinking back, I remember always losing some light with extension tubes and never when I used dioptors.

[francois_gauthier]

I would add a few comment from previous posts :

 

Your choice will also depend on what lens/lenses you will use the device.

 

The longer the focal, the longer the tube to have the same effect. I like a small one on normal and medium on short tele.

 

A tube is anoying on zooms because you loose focus when you change focal. On the other end, you can put various lenses of different filter sizes on it.

 

A c.u. is often optimize for a focal range. For exemple, Nikon 3T to 6T are for tele (probably 100 to 200mm range).

 

In any case, don't overdo it. A tube makes the circle around the captor (or film) larger. It's like cropping in the lens, so a long one reduce quality. Same thing with c.u. : over +2, the quality diminish.

 

These devices are great for close-up but if you want powerfull macro, you are better to look at other solutions like reversing rings and of course prime macro lenses.

[mark_chappell]

A closeup filter causes very minimal light loss, mainly from absorption/reflection from the

additional glass. The inverse-square law does not apply because -- unlike with extension

tubes -- you are not increasing the distance from the lens to the focal plain. It's easy

enough to verify this if you try it empirically.

 

I agree with the comment that extension tubes may, in fact, introduce distortions, etc.

Some lenses are designed to perform best at particular distances and don't do as well

when 'forced' to focus closer than their design optima. A good quality close-up lens,

such as the Canon 250D and 500D, or the Nikon 5T and 6T, can provide very, very good

optical quality. As someone said, you're not likely to achieve the excellent quality

provided by a purpose-designed macro lens, but results can be surprisingly good.

[mark_chappell]

.. or focal <B>plane</b>. oops.

[lester_wareham]

Yes as firstly correctly stated closeup filters do not reduce light, I would generally say that tubes are a better way to go in terms of quality but once you have had a macro lens you will find tubes limiting.

 

I would recommend the Canon 100mm f2.8 Macro if you want to go that far.

 

I often use tubes on my 300mm f4 IS however when I want lots of working distance, my advise is to go for the Canon tubes, the 3rd party tubes I had to start with did not lock firmly and I had a number of unscheduled lens dismounts.

[awindsor]

Anupam,

 

The original claim you made is that there was no light lost from reversing a lens on the front. This is definitely false unless you are reversing an f1 lens. However a close up lens does not cause any "light loss" (except the very marginal transmission loss). This is one reason that they are used in cinematography since they require no alteration in scene lighting (the t-stop of the lens remains the same). I tried this out and don't get any exposure change stacking dioptres until vignetting kicks in.

 

Weiyang,

 

How much magnification do you want ?

 

While short lenses with extension tubes can give high magnification they have appallingly small working distances (which can make lighting difficult). For example at close focus the working distance of a 50/1.8 with an EF25 tube is 10 cm and the magnification is .68x. On a 35/2 at close focus you get 1x with an EF25 but working distance is less than 4cm.

 

On longer lenses the gain in maximum magnification is proportionally less. I use a 70-200 with a 20mm extension tube as my standard lens for flowers. A close focusing long lens (300/4 IS) and a dioptre will get you near 1:1 very quickly but you are restricted to short working distances and higher magnifications (the 500D moves infinity focus to 500mm). Still for high magnification this is probably the way to go.

 

On my 300/4 IS the *minimum* magnification with a 500D is about .6x which is a bit much for large flowers - I want less magnification and longer working distances!

 

Each has it use.

[john_schwaller]

Here is a great calculator which will let you see the effects of TCs, extension tubes, and close up lens with different focal lenght lenses.

 

http://ca.geocities.com/lokejul/jlcalc.htm

 

Also, here is an article which talks about extension tubes and closeup lenses and compares the Hoya Closeup lens set favorably with the Canon 500D. The monocoated sets work just fine and are <$90 for a 77mm set ( http://www.2filter.com/prices/Macro_Close-up_lenses.html )

 

BTW....consider the Kenko extension tube set relative to the Canon individual units. ~$115 at http://shop.vendio.com/hkd/item/845898466/index.html

 

John