2Xmk II and the 12 and 25 extension tubes

[the photo addict]

Guys, I am really confused about this. What is the difference

between these 12 or 25 extension tubes and the 1.4x or 2x MKII lens

extenders? I own the Canon 1.4x MKII one and am happy using it.

 

My only telephoto lens is this EF135/f2L. Can any combination of

these darn "extenders" help me to reach the focal lengths the EF70-

200/f2.8L IS give me? I have been driven crazy by this question as I

dread carrying the bulk of the latter. I'd be the laughing stock of

my wife if I buy it and yet leave it at home because of its weight.

 

I am not considering the EF70-200/f4L for lack of the legendary IS

since my hands shake (I do weight training and friends say it

worsens my hand shake). Therefore deep down I really want to try and

own an IS lens.

 

Incidentally my other lenses are EF16-35/f2.8L and EF50/f1.8 II on

EOS 30 and 10D. I plan to buy a 1Ds in a year or so's time when the

price drops down to US$4000.

[NK Guy]

Extension tubes let you focus closer to things. They do not alter the focal length of

the lens.

 

Teleconverters essentially lengthen your focal length.

 

So what do you want to do? Take photos of stuff close to you (eg: macro work) or

stuff far away from you? It sounds like you want the latter, so buy a TC (Canon's TCs

are compatible with the EF 135 2L) and you'll get

a longer focal length lens, albeit at the cost of some light.

[the photo addict]

Ah Guy, thanks. Now I know. Then can the 12 and 25 extension tubes shorten the focal length on my EF135/f2L down to 70mm or so? How is that calculated roughly?

 

What would be the corresponding degradation in terms of image quality?

[bill_goldman]

Extension tubes do not shorten nor lengthen the focal length of your lens. They allow you to focus closer to your subject. They can be used singly or in combination, depending how large you want the subject to be on film or digital media.

 

The extenders 1.4X and 2X convert your lens to a longer effective focal length with an attendant loss in f-stop. Your 135mm f/2L will become an effective 189mm f/2.8 lens while the 2X will allow it to become an effective 270mm f/4 lens. You will get a slight degradation of image quality with the 1.4X and a more noticeable degradation with the 2X.

 

Neither of these devices will turn your prime (single focal length) lens into a zoom lens.

[NK Guy]

>Then can the 12 and 25 extension tubes shorten the focal length on my EF135/f2L

down to 70mm or so?

 

Please re-read what I actually wrote:

 

>Extension tubes let you focus closer to things. They do not alter the focal length of

the lens.

[frank_forester]

Julius,

 

with all due respect since you have already spent around $4000 on camera gear you might want to spend another $20 on a book or 2 about basic photography. It will clear thing up for you.

[anthony_thornborough1]

The EF 12 & 25 Extension tubes are just rings with electrical contacts so that the body can still "talk" to the lens and vice versa.

They shorten the minimum focusing distance, they don't change the focal length.

Eg a lens that normally focuses between a minimum of, say 4ft and infinity might focus at between 1ft and about 20ft with an ET on it. That allows you to get closer to the subject - cheaper than buying a macro lens if you don't want lifesize images, and it's good for flowers, close-ups of people's faces etc etc etc and is a highly cost-effective answer to getting close and packing a small kit bag.

 

If you want to extend the focal length of your lenses you need the EF 1.4X LII or EF 2X LII Extenders (more commonly referred to as converters). These will increase the focal length by 1.4 or 2 times respectively. Their use is to bring subjects that are far away a bit closer in the viewfinder and film/sensor, so that you don;t need to enlarge the image as much afterwards to get what you want.

 

Hope this helps. I think Canon's use of the term 'Extender' is confusing to beginners

[the photo addict]

Thanks to Bill, Tony, Frank, & Guy for your valuable inputs. It has dawned on me that those 12 and 25 extension tubes were called "close-up lens attachments" 30+ years ago when I read my basic photography books. I wish Canon had used more meaningful names that distinguish them from those true lens extenders thereby not confusing this old chap. Nevertheless, it is a good idea for me to re-read some basic photography books. Thanks much anyway.

[mike_smith2]

No, close up lens attachments are magnifying lenses (ie similar to filters) that attach to the front of the lens. they actually magnify the image like a magnifying glass

 

Extension tubes attach to the rear of the lens and allow the minimum focal length of the lens to be shortened. It is the shortening of the focal length that gives the magnification effect by placing the subject closer to the lens.

 

eg Many wildlife photographers use extension tubes on long focal length lenses to allow them to focus on near subjects, typically small birds, eg a telephoto lens that would have a minimum focal point of 5 metres with the addition of extension tubes can usually focus much closer say 2 metres depending on the tube used.

 

the 12 mm tube decreases close focus a small amount.

the 25 mm tube decreases close focus by a large amount.

 

the tubes can be stacked (or combined) to give even greater effect, but you have to be carefull that too much extension does not cause vignetting (darkening of the image edges). The shorter the focal length of the lens, the greater the risk of vignetting when using extension tubes, but the greater the "magnifying" effect.

 

Beware buying non Canon items, typically sold in sets of three rings, especially if using the wide aperture L series lens they will undoubdely give vignetting as usually 3rd party attachments have a narrower tube and will impinge on the image. You will also find they will not fit the teleconverter extenders you have as these have protruding lens elements which would foul party "tubes" (my experience with Pentax -L series teleconverters)

 

regards

 

Mike Smith

[the photo addict]

Thanks Mike for your detailed explanation. I have also read three different photography books I recently bought and finally cleared up my doubt over telephoto lens converters, extension tubes, and close-up diopters. Since I have not used most of these lens attachment gadgets before, it took me a while to understand their usage. Thanks for putting up with my ignorance.