Extension devices
Minolta Auto Bellows I and Focusing Rail I
with SR-T 303 and MC Rokkor 58mm f1.4
Extension is the most practical way to achieve greater magnifications with relatively short lenses. The longer the lens, the more extension is needed between the body and the lens to achieve certain magnification. So a 100mm lens needs twice the length of extension needed for a 50mm lens to achieve the same magnifications (this is not quite true due to the lens own focusing helicoid, which effects the calculation, but basically it is true). The idea of using longer lenses is that not only is the extension needed longer, but also the working distance between the lens and the subject is longer - with a 100 mm lens also it is twice the distance available with 50mm lens. You can easily imagine the difference this sc.. free distance makes when photographing insects and other moving subjects. The drawback is, that adding extension reduces the effective aperture of the lens - that is, you get less light to the film.
I have found that the 100mm is about the longest lens to be practically used with extension tubes down to life size - even longer lenses can be used, but the extension required gets unpractically long. Of course, with smaller magnifications the longer lenses can also be used. For greater than life size, I would use only normal lenses with extension (preferably reversed) or then longer lenses with reversed shorter lens attached - technique called "lens stacking".
One myth of the photography is that adding extension between the lens and the camera does not deteriorate image because there is no optics added. In fact, all the failures the lens makes are magnified. The lens is also used at closer focusing range than it has been designed for, which means the optics do not correct all the failures appearing. This is due to the fact that the angle of light rays coming from a close subject compared to lens optical axis is to big - the lens is usually optimized to a subject at infinite distance.
Extension tubes
The easiest way to start with close-up photography is to buy a set of extension tubes and use them with your 50mm lens. This way you can achieve rather large magnifications, up to 2:1 (two times life size). The normal way is to purchase a set of three tubes. Minolta has offered three different sets: two sets of manual extension tubes and automatic extension tubes.Extension Tube Set for Minolta SR
This is the original set for the first Minolta 35mm SLRs. I have only shortly examined it. It comes in a box covered with green velvet, and the exterior of the tubes is polished metal - it looks like a jewel. Neither automatic diaphgram nor meter coupling can be maintained with these rings, so the metering must always be done stopped down.
There are five parts in this set. They allow 9, 14, 19, 29, 38, 44, 53, 59 and 66 mm combinations. The three longer tubes have threads in their ends. For mounting to Minolta body and to mount a Minolta MC or MD lens there is two adapters - like the Extension Tube Set II, which is functionally similar than this series, except for the length of the tubes.
Minolta Extension Tube Set II
Photo by Joe Sutherland
There is no any kind of automation available with these extension tubes. Their outer finish is black.
Minoltas automatic extension tubes have male bayonet in one end and female bayonet in another, so they need no adapters to be used. They can be used alone or in any combination, and retain both automatic diaphgram operation and meter coupling - the metering and focusing can be used as normal. The shutter priority mode in XD or Program mode in X-700 cannot be used (although they might give right exposure due to final check.) Thickness of the tubes are 14, 21 and 28mm.
These are usually automatic ones. I have one set made by Vivitar - one of the rare non-Minolta equipment I have. They work excactly like they should. If the mechanical structure is sufficient, there is no difference compared to original equipment. My set actually maintains also the MD pin coupling, but I cannot see a reason to use it.
Bellows units
Minolta has two types of bellows units: Auto and manual bellows. The Auto Bellows units offer automatic diaphgram - that is, the metring and focusing is through the lens with full aperture, and the aperture closes down automatically to the preset value when the shutter release button is pressed, but before the shutter opens - just like normal lenses do. The difference to normal lenses or automatic extension tubes is, that the bellows units never maintain the link between the lens aperture ring and the exposure meter of the camera, so the meter does not know how much down from full aperture the lens is set. This requires some additional care from the photographer, and the procedure required varies depending on the camera body used.Bellows set for Minolta SR cameras
A simple bellows set from the beginning of Minolta SLR era, no other
information.
This is the earlier version of auto bellows, designed during the SR-T era - it works best with SR-T, XE and XM bodies. The bellows are set to a very rigid dual rail system which allows very precise extension setting. The automatic diaphgram system is made with a metal rod running below the bellows and connecting the diaphgram pin of the camera to the lens diaphgram pin. It is usually sold together with Focusing Rail I, that has similar rigid dual-rail system than the bellows unit and that allows the precise setting of desired distance from the subject - it moves the whole camera body/bellows unit/lens-system as a single unit. There are also a slide copier unit and macro stand unit designed for this bellows.
The picture at right shows the bellows with Minolta XE-1 and TC Rokkor 135/4 lens, adapted with 39mm to 42mm thread adapter and Minolta P-adapter. At the photo the lens is focused at infinity! The focusing is done solely with the bellows unit.
Some users have reported difficulties to fit X-700 together with MD-1 motor drive to AB-I - the back of the bellows unit protrudes rather far back and the MD-1 battery department is a little bit thicker than the X-700 body. I have used the AB-I with its focusing rail together with X-700/MD-1 and XD/Winder D with no difficulties. The slit between the winder/motor drive and bellows unit is narrow but it is there. However, if you think about using the bellows system with these cameras with motor drive or a winder, make sure they fit.
The Auto Bellows I connects the lens diaphgram control pin to the lever in the camera body. Therefore the focusing and framing can be done at full aperture. Because there is no connection between the MC tab of the lens and the meter coupling pin of the body, the metering must be done by the stopped-down metering. With manual exposure setting you can either shoot the lens stopped down or open the aperture up for final framing and focusing, but with automatic exposure you should leave the lens stopped down for correct exposure - except the X-700 and XD cameras, which have the final check system.
The Auto Bellows I has the maximum extension of 154 mm, which allows magnifications up to 3,1x with MC 50mm lens (3,8x if the lens is reversed), 2,7x (3,3x) with MC 58mm and 3,8x with MC 50mm Macro Rokkor. The Auto Bellows Rokkor 100mm f4 can be focused from infinity to 1:1 (1x) using the bellows - I have not formally tested the 135/4 TC RRokkor, so I cannot tell how big magnifications it can produce with this bellows unit. They aren't very big, though, less than 1:1.
The Auto Bellows I is a precise instrument, heavy and a bit unpractical to use at the field. It is therefore best fitted to inside work. It also has one very nasty drawback: The rear standard, where the camera body fastens, is fixed (it cannot be moved along the rail). Therefore the extension must be controlled solely with the front standard. If you are using a short-focal length lens (shoter than 85mm or so), you will find out, that with short extensions the front of the rails extends fruther ahead than the focusing plane. It prevents picture taking with such extension and lens combinations, if you cannot get the front of the rails past the subject. The AB III has moving rear standard, so this problem can be avoided with it.
This
is fully manual bellows unit with simpler rail and lighter construction
than the AB I. It cannot be fixed to the Focusing Rail I, but other accessories
of the Auto Bellows I can be used with an adapter. It does not have the
auto diaphgram system of the Auto Bellows I, but it extends up to 180 mm
giving therefore larger magnifications than the Auto Bellows I. It is also
a lot less expensive.
The original of the photo at left is taken by Joe Sutherland.
Minolta Auto Bellows III unit is developed specially to work with XD series cameras. It has many differences compared to AB I: The rail is a simpler construction and also a lot lighter but less sturdy. The front column (or standard, in which the lens is attached) can be shifted and tilted to control the DOF similar to large format cameras. The rear column can be moved, which allows the use of shorter focal elngth lenses and short extensions, unlike the AB I. The automatic diaphgram works by a special shutter release cord. The first cord - a standard mechanical cord - attaches to the front column and stops the lens down. This, in turn, pushes the second, special release cord forward. It's female end attaches to the opposite side of the lens column than the first cord, and the other - male - end attaches to the camera's releaase cord thread, and releases the shutter. This is necessary because the mechanical rod like in AB I would not allow the front column to be tilted or shifted.
Due to different rail also the focusing rail is different, as well as the macro stand and slide duplicator. This bellows is the choose of XD and X-500/700 cameras - the better DOF control available via moving front column is a great help. It is also possible to turn the camera for vertical shots, maintaining the bellows unit in horizontal position, which keeps the system in better balance. There is no reason not to use this with older SLRs either - like there is no reason why the AB I would not work with newer bodies.
This unit is otherwise similar to Auto Bellows III, but does not have auto diaphgram system, and is therefore a little bit less convenient to use. On the other hand, it can be used with such Minolta SLR cameras that do not support stopped-down exposure metering or do not have the final check -operation. It is recommended for XG- and X-series cameras without the DOF preview. For XG-series it is the best choose, because they don't have metered manual exposure - you can use the aperture priority AE without any corrections.
This is a small bellows unit without any auto function and also without a rail system - its length is controlled by pulling it to the right length. It is a light and easy-to-carry choise for a portable system. Without the rail system it cannot support heavy lenses at long extensions - the whole system has to be fixed from the camera's tripod socket.
Some third party manufacturers offered bellows units in Minolta mount
- at least Novoflex is a known manufacturerr. As far as the mechanical construction
is sufficient, there is no reason to avoid using them.
More about close-up photography and Minolta
| Close-up main page | |
| Minolta SLRs | About different Minolta manual focusing 35mm SLR cameras,
specially in terms of close-up photography |
| Macro lenses | Different macro lenses available for Minolta manual focusing SLRs |
| Other equipment | Other close-up equipment available for Minolta MF cameras |
| Photos | Some of my close-up photos |
My other pages
| Home | My home page. |
| My photos | My photo pages |
| Subjective lens evaluations | of some Minolta's lenses |
| Minolta XE | The finest Minolta ever made |
| Tele lenses | of 300mm length of longer for manual focusing Minolta |
| Links | Yes, links. |