Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: aboudd on April 26, 2014, 08:35:01 am

Title: Extension tubes as an alternative to macro lens
Post by: aboudd on April 26, 2014, 08:35:01 am
I just posted a piece with photos on my blog discussing extension tubes as an alternative to macro lenses. This came about as I was considering yet another macro lens purchase and someone suggested using extension tubes instead. I picked up a used set of Kenko tubes and gave them a work out this morning.

To summarize the article -

The advantages to using extension tubes in place of a macro lens.

Small size and weight
Ability to use on more than one lens
Ability to stack tubes to increase magnification ratios
A helluva lot cheaper than another lens

Disadvantage in comparison to macro lens:

Macro use only
Very limited focal range, close-in use only
AF function has a tendency to hunt
More cumbersome, slower to use
Light loss increases with each tube size increment

If you have interest in this subject, I invite you to visit the blog: www.foto-gizmo.blogspot.com
Title: Re: Extension tubes as an alternative to macro lens
Post by: Fine_Art on April 26, 2014, 12:58:25 pm
I would like to know about people's experience with fine detail using an extension tube on a regular lens. Is there a noticeable increase in aberrations? With a macro lens you are using it as designed, with extensions you are going outside the lens design parameters. Compare the detail of a lens with and without extensions. As good or worse?
Title: Re: Extension tubes as an alternative to macro lens
Post by: aboudd on April 26, 2014, 07:28:14 pm
It depends on the inherent characteristic of the lens used. This was shot with a 200MM 2.8L lens (not a macro) and 32MM extension tube combination. I don't see any issues with the resolution or sharpness. Shot on a tripod of course, 1/13th of a second at F10.
Title: Re: Extension tubes as an alternative to macro lens
Post by: Bart_van_der_Wolf on April 27, 2014, 09:14:38 am
I would like to know about people's experience with fine detail using an extension tube on a regular lens. Is there a noticeable increase in aberrations?

Hi,

An extention tube, which has no optical elements, just creates some distance to get a central part of the exit pupil's rays projected further away, larger, on the sensor. Those rays coming from a closer focused object are then in focus at a larger distance behind the lens. When the lens is no that well corrected for close focusing, the image quality will be less as well as shown larger.

A macro lens is generally (also) corrected better for closer focusing, and it usually allows to extend the lens without additional accessories.

Cheers,
Bart
Title: Re: Extension tubes as an alternative to macro lens
Post by: LenR on April 29, 2014, 09:33:27 pm
I've been a commercial studio photographer for just under 40 years.  Extension tubes have always been an integral part of my camera system.  All my lenses are medium format Zeiss and the quality is just as good as when not using them.  There may be a difference scientifically but in all my years in the business i've never seen any deterioration and no one has ever complained. 
If you need to get closer try an extension tube... you might be surprised!
Title: Re: Extension tubes as an alternative to macro lens
Post by: Photòr on June 21, 2014, 12:49:16 am
... Or try a bellow. Unfortunately nowadays bellows are not so often available for some gears (e.g. Canon EF).

Matteo