How good are the viewing lenses on TLR cameras?

I'm looking for inexpensive taking lenses for astronomy uses such as

meteor photography and star trails. The lenses will be always used

wide open. Does anyone know how good the top viewing lenses on twin

lens reflex cameras would be for use as a taking lens? I don't need a

shutter since I will be using my hat for the shutter. I will be

building a simple fixed focus body with a Mamiya or Graflex roll film

back. Can any of the interchangable types (Mamiya C220, C330) be

flipped over to try the viewing lens as a taking lens?

What's wrong with using the taking lens from a Mamiya C220 or C330? You would be much happier with the results. The viewing lenses are not made for taking pictures and probably have all sorts of distortion which to the eye gets corrected by the brain so you don't notice. The objects you will be photographing are merely pin points of light and distorted may show up as masses or jagged lines etc.

I'm intrigued. Why would you want to do this when you could just focus the TLR at infinity and use it as is? Do you intend to couple the body to some other device? If so a 35 mm SLR or even a Pentax 67 will usually be more versatile. The lenses will only cover 6*6 cm so why build another body? If you have to buy bits and pieces including a roll film back I doubt if you will save money. I would have thought that sky fog (due to light pollution) would be the limiting factor for exposure duration. The meteors will be quite bright so you may find that the probability of photographing one is increased by stopping down and exposing for longer. My experience of using fast 50 mm lenses in 35 mm for astrophotography is that they all suffer very noticeably from off axis coma wide open and are best stopped down to a least f2.

my strong advice is to contact lens & repro in nyc and buy an excellent, cheap LF lens in barrel mount. you can get any focal length you want and the lens should come with flange, etc. for easy mounting. the optics will be far better than any tlr viewing lens, and the coverage will be far greater. if you already have a mamiya to cannabalize and that is why you mention the idea of using a tlr viewing lens, i will tell you what i have heard from others: there is less difference in quality between the taking and viewing lenses of a mamiya than many other tlrs. rollei, for example, used far far better lenses for taking than viewing in its tlrs. you might give the mamiya a try if you have a victim ready to go on your workbench. if not, i'd definitely consider going for a LF barrel lens. high quality and cheap -- what more can you ask for?

It would be worth riging up something like that if you had a quality lens to use:

 

I have a Novoflex leica made linse 400mm f5.6 lens head. This has a rear element about 70mm across, a foot from the film, so I imagine it might cover 6 x 6cm. For night photography I could use a hat as a shutter, or a focal plane Hasselbald (if I had one) or (for long or flash exposures) the secondary shutter of my ELD motor-blad.

I think John was looking for an inexpensive solution i.e. not one involving Hassleblad Novoflex etc. I suspect he wanted to use the viewing lens of a TLR because they are faster than the taking lens. Even if he already has a non-working TLR to cannibalise, it may still be cheaper to buy a partialy working (even if the shutter will only operate at B setting) one used and use it as designed. Also I don't know why 35 mm would not be adequate for this purpose (faster lenses better availability etc.)

vartan makes excellent points. you mention, however, using mf film backs and unfortunately the 35mm lenses won't cover. lens & repro has dozens of barrel lenses of the highest quality for under $100. their telephone # is 212-675-1900. midwest doubtless has some deals too.

Actually, on a lens for a Mamiya TLR, the viewing and taking lens are the same

optics, although I wouldn't be floored if the taking lenses are the

ones that passes the most stringent quality control requirements.

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I don't see why a viewing lens would save you $. Whether you remove

the viewing or taking lens from a non-interchangeable lens TLR, you

render the camera unusable either way, and the same goes for a Mamiya TLR

lens assembly.

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But if you want something that covers a 6x9 roll film holder, you'll

need a wider coverage. Since you wish to use Mamiya roll backs,

why not just use a mamiya press camera and lens and save yourself

alot of trouble. these cameras are inexpensive on the used market,

and they are fully mechanical, so you won't have to worry about a solenoid

draining your battery for trhe duration of a long exposure.

The 100/2.8 lens for these cameras is a planar-like design and should

be the best corrected wide open of the mamiya press lenses.

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for 6x6 and 645 you can get f/2 and f/1.9 lenses, by the way.

The MAmiya 80/1.9 is the most cost-effective of these.

The Mamiya lenses are the same; if you find a lens that has a trashed taking lens but a good viewing lens you're in business.

 

I think the longer ones may barely cover 6x7, probably not too good out in the corners; 6x9 is doubtful.

 

The easy way is to simply use a Mamiya Press or Graflex XL.

Thanks for all the helpfull answers. The reason that I don't want to use a standard medium format body is because of the need to modify the body for astro purposes. I would like to operate without batteries because of the long exposures(hours). Purging the inside with nitrogen will keep the film from absorbing water vapor and loosing speed during long exposures. I may put a very low level red LED inside the body to help along long exposures. I need to heat the camera to a degree or two above the dew point or it will get wet. Finally, I might put a small CCD inside the body to automatically track the stars or comets. I found the other night during the Leonid meteor shower that a Pentax 67 with 105mm f/2.4 lens caught many more meteors than a Pentax LX 35mm camera with a 50mm f/1.4. I guess diameter is worth a lot more than f/no.

OK....rather than use a TLR lens I'd suggest you find a lens intended for 2x3 press cameras; suitable candidates include the normal-to-wide lenses for the Mamiya Press (Press, Press 23, Universal), the 80mm f2.8 Planar and Heligon lenses for the Graflex XL and Linhof 23.

 

These lenses are in leaf shutters, which of course you could simply lock open for long exposures, they're good on 6x7 and ok on 6x9, and of course if you obtain a lens in/on its focusing barrel you can either use the barrel for your camera or easily remove the lens from the barrel and mount it however you want.

 

One thing you need to consider is film flatness; the old Graflex rollbacks aren't great shakes for flatness. The leverwind versions are the best of those. The modern Horseman/Wista etc rollbacks (same mount) are much better in that respect. An alternative, if motorized operation would be better, is the 6x7 self-contained motorized rollback for the Mamiya RB.

You have some interesting ideas, about using nitrogen purge, led's for preflashing etc, but I believe many people have had sucess using gas hyper-sensitised technical-pan film with normal cameras. If you use dry nitrogen purge you should be able to cool the film without fear of condensation, and this will reduce reciprocity failure. you could use dry ice or perhaps a Peltier effect device. Of course it may be a nice project to go for the DIY approach. I would be interested to know if you are sucessful.