Macro Bellows

by Johan J Ingles-Le Nobel
Last updated August 31, 2017

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A bellows set is an old fashioned piece of apparatus that most of the major brands don't even make anymore: a manual piece of photo kit that allows us to move a lens closer and away from the sensor, which decreases and increases the magnification that the lens will eventually render. A longer, stretched out bellows gives you greater magnification, whereas a compressed bellows gives less magnification. There are good bellows and there are also some very bad bellows: a decent set makes your life a ton easier than a cheap set with a lack of controls.

Extreme Macro Bellows

Bellows

Pentax-M series bellows, an old 1970s piece of equipment that is beautifully crafted and still gives an excellent performance almost 50 years later. The removable bellow is worthy of note, as it means you can add a Raynox to add an infinite tube very easily. They don't make things like this as well as they used to.

A Bellows is actually by definition a macro piece of gear, but there are certain things that you should look for in a good set of bellows to make your life as easy as possible. I started out with a basic M42 eBay ex-soviet bloc 'solid as a brick' cheapo myself which was fun whilst it lasted, but once you move onto a decent set you won't ever wish to look back.

3 Way Adjustment

The best sort of bellows that you can buy for extreme macro have at least 3 adjustable plains of movement on the knobs: one in which the front ring/adaptor (on which the lens sits) can be moved backwards and forwards, another the back ring/adaptor (on which the camera end sits) can be moved backwards and forwards and the whole mechanism (ie the rail both the front and back rings sit) can also independently be moved backwards and forwards. Bellows like this are made for various brands so choose the right brand to fit your gear - I use the Pentax ones because I use a Pentax. The best sort of bellows that you can buy for extreme macro have at least 3 adjustable plains of movement on the knobs

For extreme macro you want to have as much of this adjustability as possible as it allows you to get set up nicely in terms of working distance, and set up nicely in terms of tweaking the magnification. Most cheap bellows sets only allow movement in the rear connector (nearest the camera) but if you can, go for one that permits both.

Beyond having the three way adjustment on the bellows, the next nice things to have are a very smooth backwards and forward movement adjustment, and the ability to lock position with a second tightening nut on each of the axis that can move. There are bellows available that also to tilt shift and these might be useful for manipulating the focus plain on high magnification images, although it seems likely that you'd require some very special optics to use them effectively because of the increased area you'd need.

Macro Bellows Calculator

Bellows length added, in mm (ie 75):
Focal length of your lens, in mm (ie 25):
Macro magnification ratio of your lens, :1 (ie .5 for 1:2):
F/stop that you intend to use (ie 8 for f/8):

Using bellows at this length gives you a new macro magnification of and a new closest focusing distance of When used with your intended f/stop, the effective f/stop becomes

The Downside

improve your bellows by adding an internal baffle that cuts out excess stray light

Bellows don't usually pass electronic information between lens and camera, so you'll need to adjust your aperture manually or know what you're doing in terms of f/stop. For extreme macro focus stacking this really doesn't matter too much as we tend to use lenses at whatever settings they give the best result at and stack the shots, but for bellows use with less extreme macro this may present difficulties.

Macro Bellows: What To Look For

There are some other things worth looking for if you're going to invest in a decent set of bellows. They're not exactly deal breakers but they help to make your life easier. Some bellows have a removable rear adapter which unscrews with a little bolt - it makes for a nice convenience when getting set up. A reversible mount is also a nice luxury - rather than having a brand-specific end, just turn it round and you have M42. A strong solid precise rail needs no further elaboration as to why it's useful, and also two little somethings that I quite like on my Pentax bellows: a measuring scale so you can record the bellows extension you used, and stops at the ends of the rail means you don't actually position your cam off the rail... which wouldn't be great...

It's also worth mentioning a small extra which I have on my most excellent Pentax-M bellows, which is a filter connection on the inside of the front ring. This gives me the added versatility to for example put in a Raynox to add as a tube lens and to connect it securely. Very nice to have. One thing of note about the Pentax-M bellows, sadly the parts are not interchangeable with the Pentax-A bellows, there is a 3/64 inch difference in X rail dimension which means they don't work when transferred across to the other bellows.

Improving Your Bellows

You can marginally improve your bellows by adding an internal baffle that cuts out excess stray light. My baffle is made out of black cardboard and makes the internal opening of the bellows smaller. This means it cuts out reflections and any cruddy light. These are often responsible for the gray layer and poor contrast that you see on bellows shots with light contamination. My baffle is towards the lens end and this works for me but maybe having two baffles, one each end, would work even better. Trial and error is your friend.

Older Bellows

One thing that you do need to bear in mind that by buying an old set of bellows from the 1970s such as the Pentax-M bellows, you're buying a piece of equipment that's almost 50 years old so it may not be terribly surprising if it's seen better days. For example the accordion on my old bellows is made of paper and the folds can and do wear out because of their age. There's a great place in England that you can send your bellows to though, which will make you a bellows new accordion. Beyond that, it's also possible to repair your old bellows using liquid Stitch for large gashes, a coat of black fabric paint (ie tulip), a coat of mixed Elmers Fabric Glue (flexible, stretchable glue) and a couple more coats of black fabric paint to cover the grey back up. Old bellows will also benefit from the odd bit of tightening up here and there with a small hex key - in my case the rack and pinion control handles had loosened over time so it seemed like the teeth might have gone but in fact I just needed to screw the side nut a little tighter. Also, old bellows do benefit from an internal spray job - sometimes they can develop small holes over time and a quick spray of the accordion with black fabric paint, available at many arts and crafts stores, can repair slight cracks and pinholes.

Comments (11)

Article: Macro Bellows
Wpresto says...
A good source for M42 to RMS and I think also to Leica (M39) thread: www.thorlabs.com. Purchased two M42/RMS adapters, The machining is good, nice smooth operating threads. I have a Pentax-made M42/Leica thread adapter, so I didn't search for one. Also, I have a Pentax-made K to RMS adapter, but the bayonet end is very tight - difficult to mount fully, and very difficult to remove.
29th January 2014 1:10pm
Petrochemist says...
Johan, I think this page should be directly accessible from the Equipment dropdown list. I couldn't find it there but found it via a link on the extension tubes page.

Overal an EXCELLENT website BTW.
26th November 2013 3:24pm
Johan says...
Thank you! It's there, under stages
26th November 2013 3:54pm
Petrochemist says...
So it is. Where abouts do you mount your light baffle in the bellows? Is it right at the camera end or part way along...
27th November 2013 9:37am
Johan says...
I made mine to fit at the lens end, but as small as I could get away with - under the assumption that the bellows accordion material probably absorbs any excess beyond that so I was really more concerned with cutting out the internal metal reflection from the front components. Other opinions/ideas very welcome =)
27th November 2013 10:49am
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