[GatorPentax]

I've been considering purchasing a macro lens but being that they are at least $300 -$500 the plan has taken a back seat. So i was at the Smithsonian Natural Museum the other day and they had a special gallery of award winning photography. All were blown up to Gi-normous sizes and looked amazing. Many were student photographs and national geographic photographs.

I was reading the captions on these photos and noticed that they were obligated to put down the equipment they used, and i noticed that a few use "extension tubes" and not the traditional macro lens. These pictures were beautiful!

My question is, if "award winning" photographs can be obtained using an extension tube, whats the purpose of a macro aside from being able to capture more light faster?

Does anyone here have experience with extension tubes?

[Buschmaster]

Afaik, extension tubes dont compensate in the way that macro lenses do. I forgot the actual term...

[ChrisA]

Does anyone here have experience with extension tubes?

They're an inexpensive way of getting very close to the subject, and achieving some quite surprising magnifications.

There's no glass in them, so there's nothing to degrade the image, compared with some of the snap-on close-up attachments you can buy (although I've seen others' excellent results obtained with these too).

Macro is a whole new world, and not one to lash out huge amounts of money on until you know you really want to get into it in a big enough way to justify it.

I started with tubes, and have found them excellent. I've used them with a 50mm SMC-A lens, and also with a 28mm lens reversed on to the end of the tubes with a reversing adapter (also inexpensive). I have a Pentax SMC-A 100mm F4 Macro lens, but I use the tubes a lot more.

Here are a few shots I've taken with them. Not competition standard by any means, but I was pleased with them as a start:

[Mikhail]

It all comes down to working distance... Macro lenses give you a greater working distance to magnification ratio compared to ext. tubes.

Thanks

[Lowell Goudge]

while not necessairly "macro" photography, extension tubes let you do something else, especially with long lenses.

I have a 400 mmF/5.6 which normally can only focus to 20 feet. by adding extension tubes, I can focus closer. this is a great advantage, because for some subjects, I can actually get closer than the lens can focus, but still not fill the view finder (birds are one thing that gets in this catagory)

You may find more uses than just true macro.

For macro work, you may actually find yourself using combinations of extension tubes and macro lenses depending on subject.

Extension tubes are a good low cost entry into macro, as are close up lenses (1, 2, & 4 diopter filter mounted lenses) and reversing adaptors.

You can also shop for a manual focus macro lens (SMC-M 100mm F4 comes to mind) because many times you will want manual focus any way, and the cost will be much lower.

I have yet to purchase a new macro lens after 20 years, but do have the 100mm F4 (bought used), extension tubes and close up lenses.

[Tom M]

I've been thinking of getting me some extension tubes.. I'm currently enjoying the vivi 105 macro but, I have noticed something. The in-focus area is extremely tight, even stopped down. I'm having great success with it but, I'd like to bring more of the image into focus. Maybe an extension tube on one of my 50's or the 28 would get me this? Thoughts?

[Lowell Goudge]

I've been thinking of getting me some extension tubes.. I'm currently enjoying the vivi 105 macro but, I have noticed something. The in-focus area is extremely tight, even stopped down. I'm having great success with it but, I'd like to bring more of the image into focus. Maybe an extension tube on one of my 50's or the 28 would get me this? Thoughts?

I think I have asked this question before, and not seen any proof, but if you take all possible macro methods,

- extension tubes
- macro lens
- close up filter adaptors
- reversing rings
- different focal lengths

what, for a given image size produces the best depth of field.

clearly extension tubes on a lens, are equal to a macro lens of the same focal length, because that is essentually what a macro lens is, a lens that can move the elements further from the sensor/film, but of the other approaches, what wins?

[jgredline]

Hi folks
I am new here and already learning...I have never heard of these extension tubes, so this thread has some great info..I Yahooled this and found this Extension Tubes and Reversing Ring (Long, 9 Photos): Pentax SLR Talk Forum: Digital Photography Review
Now the question is this...Where can I buy a set?

[Eaglerapids]

Roy has a set for sale here:
https://www.pentaxforums.com/forums/photographers-marketplace/12957-fs-couple...tar-tubes.html
I have this same set and they work very well.

[Mikhail]

I dont believe a macro lens of the same fl of a 'normal' lens with tubes is the same.
First tubes cause lightloss. About 0.1stop per mm. [ ie. a 10mm tube causes 1stop of light loss ]
Secondly you will most likely have to play around with ec due to the light loss. Also working distance on the macro I believe may still be bigger than the same lens with tubes. [ though im not totally sure about that ]. Also dedicated macro lenses are often sharper than a standard portrait lens for example. And you'll often loose autofocus [ a good and a bad thing ]

Thanks

[AlexL]

Hi folks
I am new here and already learning...I have never heard of these extension tubes, so this thread has some great info..I Yahooled this and found this Extension Tubes and Reversing Ring (Long, 9 Photos): Pentax SLR Talk Forum: Digital Photography Review
Now the question is this...Where can I buy a set?

I recently bought a set for really cheap off eBay for about $21 shipped. It works well for me.

Take note that the cheap eBay ones, although inexpensive, they don't have the contacts between lens and camera for AF and aperture control; so you'll have to use the camera as fully manual with a lens at the end of an extension tube. This is not a hindrance for me since most of my lens are manual anyway.

Much more expensive extension tubes do provide the contacts for more automatic controls.

Alex

[Lowell Goudge]

I dont believe a macro lens of the same fl of a 'normal' lens with tubes is the same.
First tubes cause lightloss. About 0.1stop per mm. [ ie. a 10mm tube causes 1stop of light loss ]
Secondly you will most likely have to play around with ec due to the light loss. Also working distance on the macro I believe may still be bigger than the same lens with tubes. [ though im not totally sure about that ]. Also dedicated macro lenses are often sharper than a standard portrait lens for example. And you'll often loose autofocus [ a good and a bad thing ]

Thanks

Time for optics 101.

The focal length of a lens is defined as a function of how far from the focusing plane the lens (simple lens actually) for an object at infinity.

F stop is the ratio (again for a simple lens) if diameter over focal length. (remember focal length is at infinity)

Any lens, when focusing closer than infinity moves out slightly. and the image projected gets larger . The "light loss" is not actually loss, but the fact that the same image is spread over a larger area.

ALL lenses actually get slightly slower as they focus in from infinity due to this same feature. The reason it is not a real problem is that from infinity to minimum focus generally is less than 1-2 mm or much less than 1 stop.

As a reault, there is no difference in the speed of a lens with extension tubes set to F4 and a macro lens of the same focal length set to F4 when focused on the same image and the same magnification ratio.

There is no need to play around with the light loss, that is what TTL metering is all about, the camera meter sorts all of that out and unless you are using manual or auto flash (non TTL) flash there is no need to play around.

Working distance will be the same for the same image size and focal length lens regardless of how you achieve close focus (with tubes or a macro lens)

I don't dispute that a macro lens is ( or may be sharper) than a standard or portrait lens (I have often advised against using macro lenses for portrait because they may be too sharp and it is not flattering to show every blemish on a portrait.

Also macro lenses are designed to be flat field lenses, used for making everything on a plane parallel to the sensor/film in focus.

[Hornet]

I have used both extension tubes and macro lenses. If using either to photograph 3D objects there is little difference in terms of the quality of the resultant images (given you are using reasonable lenses in each case).

The main advantage to me in using a dedicated macro lens is the convenience - I can focus from the closest the lens goes all the way out to infinity. With extension tubes I am constrained to a narrow range of focus distance and must remove the tube to do non-macro photography. Another advantage of macro lenses is that they usually stop down further (f32 or more) - thus allowing a greater depth of field (this is more important in macro photography than most other situations).

However I would never be without my extension tubes. They give me the flexibility to use any lens (within reason) for closeups and I can achieve significantly more magnification than 1:1 (the usual limit of macro lenses). In fact I often use extension tubes with my macro lenses to get into the 2:1 range without resorting to reversed lenses and other more complicated arrangements.

My recommendation to someone starting out in macro photography (assuming they already possess a prime lens of 50mm or greater) would be to get the tubes (or take the glass out of an old teleconverter) and if they like it, buy a macro lens. If money is no object buy both

[GaryML]

Time for optics 101.

The focal length of a lens is defined as a function of how far from the focusing plane the lens (simple lens actually) for an object at infinity.

F stop is the ratio (again for a simple lens) if diameter over focal length. (remember focal length is at infinity)

Any lens, when focusing closer than infinity moves out slightly. and the image projected gets larger . The "light loss" is not actually loss, but the fact that the same image is spread over a larger area.

ALL lenses actually get slightly slower as they focus in from infinity due to this same feature. The reason it is not a real problem is that from infinity to minimum focus generally is less than 1-2 mm or much less than 1 stop.

...

Also macro lenses are designed to be flat field lenses, used for making everything on a plane parallel to the sensor/film in focus.

Just to elaborate a little bit:

Focal length is the distance of the optical center of the lens to the focal plane at infinite focus. As you said, for a simple lens (single element) it is simply the distance of the center of the lens to the focal plane.

The "f-stop" is the ratio of the size of the opening at the optical center of the lens to the focal length. A 50mm lens with a 50mm opening is f/1 or f/1:1. A 50mm lens with a 25mm opening is f/2 or f/1:2. Again, for a simple single element without an aperture mechanism is it simply the diameter of the element.

A lens can focus by moving closer or farther from the focal plane. Modern lenses with multiple elements may focus by internally moving elements between the front and real elements, but this has the optical effect of moving the entire lens.

Close focusing does cause actual light loss as the lens is moved farther from the focal plane. However, the aperture and therefore the f-stop does not change. The effective f-stop in terms of light loss may be the loss of one or two stops, but the actual f-stop and the associated depth of field associated with the f-stop does not change.

Macro lenses are often measured by the "life size" size of the image: a ratio of 1:1 when the object in real life is the same size as the image size on the film or sensor. To achieve life size, a lens must be extended to the same distance as its focal length. A 50mm lens produces a life size image when it is moved an additional 50mm from the focal plane (and the subject is moved sufficiently close to the front of the lens). Think about that: it really makes a lot of sense given how a lens functions.

Lens extension may be from extension tubes, a bellows, a special "macro" lens with a long focusing helicoid, etc. The light loss is the same regardless of the method of extension.

Close up accessory lenses that you screw on the filter threads are just like a magnifying glass and can increase magnification without the light loss of extension. But the optical quality is usually poorer than a macro lens.

A macro lens is a lens specially designed for high magnification. It usually allows 1:1 without additional devices, is designed for excellent image quality at close focus. It is usually, but not always, designed for a flat field. It usually, but not always, provides better image quality than a regular lens with extension tubes or a bellows.

[jgredline]

Hi Folks...Great stuff...
Here is a question that I have been wanting to ask, but did not know where to ask..
On one of my Lenses a tamrom 70-300mm with a macro of 180-300..I don't really see much of a difference in the photos..Am I missing something? What exactly is the purpose of it?
Thanks again folks,
javier