The old fashioned way of obtaining close ups (using extension tubes) Updated-images

grebeman

Old Codgers Group
Yesterday, for my pains, I was given some homework by Streetshooter (Don) to describe in some detail the combinations of extension tubes that I had been using with a Kern Paillard Yvar 150mm, f/4 C mount lens I was kindly given some weeks ago.

I'm sure you all know, but for the sake of completeness extension tubes fit between the lens and the camera mount. Since this lens is an old fashioned 1950's manual focus/manual stop down lens the tubes are just that, simple tubes. There are 3 in total with lengths of 10mm, 20mm and 40mm. Using simple mathematics (the principle of addition) the lengths of extension possible are 10mm, 20mm, 30mm (10+20), 40mm, 50mm (10+40), 60mm (20+40) and 70mm (10+20+40).

Just what does this mean in practice?

The first thing is that as you move the lens further away from the sensor plane in the camera the light has to travel further and so less light will reach the sensor. Given our modern all singing, all dancing cameras the exposure adjustment necessary to cater for this will be made automatically by the camera. Phew, one less thing to think about.

Secondly as you move the lens further from the sensor plane with the tubes the lens will focus at closer distances than it would without the tubes, and it wil no longer focus on infinity. So how much by you ask?

The figures below are, in order left to right, extension tube length, minimum focus distance, maximum focus distance and approximate horizontal field of view


none, 13 feet, infinity
10mm, 58in (1470mm), 87in (2210mm), 11in (280mm)
20mm, 35in (890mm), 46in (1170mm), 4in (100mm)
30mm, 27in (685mm), 33in (840mm), 2.6in (65mm)
40mm, 21.5in (550mm), 25in (635mm), 2.25in (60mm)
50mm, 18.75in (475mm), 20.5in (520mm), 2in (50mm)
60mm, 17in (430mm), 18in (460mm), 1.6in (40mm)
70mm, 15in (380mm), 15.75in (400mm), 1.25in (32mm)

These figures are all approximations.

The 20mm extension is probably the best for butterflies and dragonflies, for damselflies perhaps 30mm or 40mm (non to experiment with now) and small flies 60mm or 70mm. Full flowers 10mm or 20mm depending on the size of the bloom with close detail using the 70mm.

I have used the lens fitted with extension tubes up to 60mm handheld, although it's perhaps best at 10mm or 20mm when it is possible to focus without using the magnified focus assist. Your experience of this might vary dependant on the accuracy of the dioptre setting in your viewfinder and your own eyesight. Above 20mm the magnified focus assist is essential (built into m4/3 cameras, no experience of others) since the depth of field is very limited. The camera is best focused by moving it backwards and forwards slightly, hence the use of a focusing rack visible in the photograph below.
Note that when used without extension tubes this lens produces some vignetting of the corners of the image, so m4/3 sensors are the limit of sensor size for these C mount lens (16mm movie lenses).

Kern_Paillard.jpg


The following series of photographs illustrates the change in the field of view as the length of the extension tubes is increased. The Honeysuckle flower is approximately 2.375in (60mm) across and the bug in some later shots is approx 0.33in (8mm) long

1040058.jpg
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10mm extension tube, 72in (1830mm) from front of lens to subject, f/4

1040059.jpg
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20mm extension tube, 36in (920mm) from front of lens to subject, f/5.6

1040060.jpg
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30mm extension tube, 27in (690mm) from front of lens to subject, f/8

1040061.jpg
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40mm extension tube, 22in (560mm) from front of lens to subject, f/11

1040063.jpg
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50mm extension tube, 18in (460mm) from front of lens to subject, f/11

1040064.jpg
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60mm extension tube, 17in (430mm) from front of lens to subject, f/11

1040066.jpg
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70mm extension tube, 15in (380mm) from front of lens to subject, f/11

I must apologise for seemingly missing the point of focus in a couple of the above shots, but hopefully they illustrate the point.

Hope the above info is of interest to some of you.

Barrie
 
I'm impressed, Barrie! The combination of arithmetic and weight would hold me back, I'm afraid:redface: - however, this "old fashioned" way is an art...and one that many of us "older" sorts will remember. That said, I personally have to say that I have never used an extension tube - but some of my best friends have - and do.:D

I shall look forward to your continued photographic journey amid field and flower...and the hills and dales...and maybe eventually a glimpse into that neighborhood pub, too.(y)

Thank you so much for laying this all out so clearly, Barrie.
 
Barrie, thanks....
Your mission Barrie, should you decide to accept is....
Please post images according to the specs you posted above. I would think the same subject would give a visual reference point to your detailed explanation.
This post will not self destruct in 10 seconds...
 
I have experimented a bit with extension tubes, and they are tricky to manage handheld. As Barrie says, the depth of field can be extraordinarlity shallow, so much so that a breath or even the natural motion of the body leeping it's balance can bring the object in and out of focus.

Two things occur to me looking at this setup - the first is about the potential for distorting the body mount (with such a lengthy setup and the weight of a "proper" metal-bodied lens there must be significant moment produced?); the second is about the rack, which looks a very nice bit of kit ... where what who?
 
Paul,

Despite being a proper metal and glass lens, it is surprisingly light at 310 grams. The Panasonic 100-300 zoom weighs in at 500 gram and this lens is no longer than the afore mentioned Panasonic zoom when that is zoomed out to 300mm, that is before any extension tubes being used, so whilst the rig looks front heavy and unbalanced, it is not unduly so. I have been mulling over the idea of some sort of frame that will fix to the camera tripod mount and support the lens somewhere along its length with a tripod mount part way along the frame so that it is more balanced. In hand held mode it is extremely well balanced.
The focusing rack is a Novoflex Castel-Mini, probably near its carrying limit, but very useful.

Barrie
 
Paul, that's a very important point about the mount. These new fangled digicams aren't made like the cameras from yesteryear. There should be a way to relieve the weight ....hmmmmm
 
Barrie, thanks....
Your mission Barrie, should you decide to accept is....

Gosh, more homework :) I think that is manageable and at least the mathematics so far has fallen well short of calculus, which I've long since forgotten how to do, so an enjoyable task I think, now to locate a subject and the correct lighting. One springs to mind, but that would require morning light, let me sleep on it.

Barrie
 
Another thought, am I right in thinking that when used on a Bolex movie camera this lens would be mounted on a turret that could be turned round to bring one of 3 different lenses into use, hence the weight was probably kept down with the idea of keeping the stress on the turret to a minimum.

Barrie
 
Barrie, correct. The Bolex was a very well built camera. I don't think they used rings in that setup but, maybe there is something available from years gone by..
 
Yeah Barrie... Waiting on Paul's ideas.....

I'm no engineer Don ... I suppose Barrie's point is well made, I use the Olympus 4/3 70-300 on my E-P2 and that's a big lump ; I guess if Olympus weren't confident about the strength of the PEN mount they wouldn't make an adapter (but that might not go for all CSC cameras of course) ... on the other hand, thinking about it I also wonder about the strength of the tripod mount on the camera when used with a lengthy/heavy lens.
I seem to remember someone at mu43 saying they'd damaged their (Olympus?) base plate this way, but can't recall the details - it was ages ago, last year sometime
 
Don, I have added the images as requested to the original post to keep everything relevant together, so mission accomplished :) Note the bug in the later very close shots, how cool is that, have to keep in with your grandson.

As for Paul's point, as a former chartered engineer, albeit an electrical one but well exposed to mechanical equipment, I'm reasonably happy with the weight and moment forces on the adapter, camera lens mount and tripod mount. I would expect more force to be put on the tripod mount by over tightening the retaining screw than the weight and turning moment of the lens. Without doing some calculations, and dusting off my slide rule :rolleyes:, the use of the Panasonic 100-300mm zoom at some 60% heavier than this set up and about the same length when zoomed out is probably going to put more turning moment on the lens mount and tripod mount than this rig.

Barrie
 
Cheers Barrie, that info is REALLY helpful. I am in the market for a macro lens, but haven't yet discovered exactly what it is I want/need to buy. I've seen tubes and converters and stuff, but haven't known what each would mean in terms of getting down and dirty.

When we're talking macro are we always talking tripod as well? I'm assuming that will be the case with the tiny tiny margins of error, but as previously stated, I'm happier crawling on my belly and using my elbows as support.

I may jump in the car right now and go to the camera place at Cowcaddens which I have never visited and harass their sales people. Merchant City Cameras is a nice wee place but didn't quite have what I'm after. Although I will be going back to buy some of their very early cameras as a present before christmas.
 
Hi,

Yes a tripod becomes an essential bit of gear when you start getting really close, and even then not every shot will be in focus. Butterflies and Dragonflies in context, in other words with some surrounding features, vegetation and the like can be hand held with some success, anything smaller really benefits from the effort required to both carry and set up a tripod. That can mean that some stuff (insects) get away, but that's all part of the challenge.

You might want to consider some sort of tripod that will get you really close to the ground when necessary, rather than the more conventional types that are just some means of holding the camera at waist height.

Good luck with your hunting.

Barrie
 
I've got a study tripod that I took out to play recently to some effect, I've also got the gorillapod that I haven't used to its full potential yet. I usually use my rucksack, my flask, the camera bag and a combination of whatever flotsam I can find. Life's too short to carry piles of kit up a hill!

I've just ebayed a little teleconverter thingy, so in a couple of days I'll hopefully show you what difference it makes. It's not the answer I don't think, but for £20 I'm not going to cry if it doesn't work.
 
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