Mamiya C330f Professional Reparaturanleitung PDF herunterladen (Seite 47)

Mamiya TLR Summary 47

Fits 105mm DS, 105mm non-DS, 80mm, 65mm, and 55mm black series. It will also fit the 65mm chrome and probably the

other short chrome lenses.

It appears that the 35mm film cans used for Agfaortho 25 around 1992-94 will fit the 65mm and 105mm chrome lenses when

cut down to around 15mm depth. Unfortunately this isn't true of current Kodak and Ilford cans.

The 'figure eight' front caps don't always fit well with filters in place. The older caps - pre-C33 - were metal, later ones

were made of soft plastic. Standard clip fit-caps can be substituted, but they may need a flat sanded at a point on the

circumference to provide clearance for the cap on the other lens. Pairs of caps can always be joined by a rigid bar or a cord.

Using stepping rings to standardise on 49mm filters usually means fitting new caps.

There are such things as body caps, though they are rare. This image of a "gif/bodycap.gif" body cap shows the general

shape. This picture of the actual item is courtesy of Stefan Geyson. To get a normal sized template, make a pencil rubbing

of the lens mount. The original caps have rims to locate the plate, but the clamp wire will suffice to hold a simple plate in

place. The main thing to avoid when making a cap is fouling the shutter linkages.

11.3 Light traps

Most of the camera backs incorporate foam light proofing and film pressure pads. The pressure pad rests against the

unexposed film spool, and acts as a friction mechanism to keep the film taut. The light trapping lies along the edges of the

back.

This material does age, becoming less resilient, and eventually powdery. Local Mamiya parts suppliers may have suitable

light trap material available.

Alternative materials:

Large areas can be replaced by a strip of hook and loop fastener (usually known by the trade name, Velcro (R)). The loop

side is usually denser.

The thin light trapping strips are hard to replace. Moral: don't damage them! A suggestion made to me recently was to use

twisted or plaited black cotton.

The fine black foam used for computer mouse mats can also be used when suitable strips can be cut.

Foam intended for camera use can be obtained from Micro Tools (http://www.micro-tools.com/), though you may have to

search for it. They have a big inventory.

11.4 Front Element Converters

Since this can be done, it seems worth a few words. But don't expect miracles!

11.4.1 Video camera lens converters

There are a number of wide angle and telephoto front element converters available for use with video cameras. Typically

these range from x0.42 and x0.5 at the wide end, to x1.5 or x2 at the long end. At least one company manufactures a

reversible x0.5/x1.5 model. Those that are fitted with a 46mm thread are suitable for mounting on the later Mamiya lenses,

either directly or via a 46-49mm stepping ring. It is possible to fit two of these devices simultaneously, but this may vary

from lens model to model. If you go this route, expect to file a flat on one stepping ring to permit the other to screw down.

It’s important that the stepping rings used are the same thickness.

Optical performance isn't great. Not surprising, since they are intended for the more tolerant video optical train. The

correction for aberrations is often poor, usually manifesting as barrel distortion with wide angle converters, and pin-cushion

on the telephoto converters. But they are comparatively inexpensive, especially if you can locate a used pair.

However, if you would like a pseudo-super-wide lens then mounting a x0.5 on a 55mm will produce some dramatic effects.

It isn't quite the 27.5mm you might expect, but it does give a cropped circular image (corner vignetting). But don't expect

sharp results. You will need to experiment to determine the light loss. Typical values seem to be around half a stop for 0.5x

or 1.5x attachments.

At the other end of the scale the aberrations seem better corrected. Adding a x1.5 to a 135, 180, or 250mm gives a nominal

200, 270, or 375mm lens. The trade off is whether the extra length gives better quality than enlarging the image from the

prime lens.

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