SP 1000, need some information

i have inherited an Asahi Pentax SP1000. i dearly love this camera, but unfortunately the light meter doesn't work which can be a bit of a bugger. i have been told that it would not be cost effective to fix it. I am looking for a replacement, but cannot find the same camera, although a lot of similar ones are for sale. Where does my camera fit into the history of Pentax? is it a pre or post spotmatic design? i am looking for something as similar as possible, and would like some advice, thankyou very much

Your questions are anwered here:

http://www.aohc.it/indexe.htm

I have an SPII with a faulty meter. The simplest solution is a second-hand meter from Ebay.

G

The SP1000 is basically a Spotmatic without the self timer. It was one of the last screw thread Pentaxes to be available, being phased out in favour of the bayonet mount K1000.

I presume you jave tried a new battery of the correct type? You would need a Wein 1.35v cell, available from Jessops and others such as the Small Battery Company. 1.5v cells that appear to fit should be avoided as they do not give accurate readings because of the higher voltage.

You could also try cleaning the battery contacts with a rubber or some mild sandpaper, and maybe the meter will spring into life. If not, it will be as cheap to buy a new body, but why not a Spotmatic, which is the sdame but with the self timer? There are plenty of those on eBay!

Actually, John, Pentax used a bridge circuit in the meters of these cameras which balances out the voltage. Within limits, the voltage does not affect the accuracy of the meter. This means that a 1.5v battery CAN be used.

http://www.aohc.it/batte.htm

The other difference between the SP1000 and the SPII (the best of the stop-down cameras) was that the former lacked a hotshoe.

G

Thanks for the link, George.

I can only report my understanding as being that the change in voltage can result in underexposure of around two stops, but I am open to correction on this!

It's probably worth mentioning that cameras from the M series should not be used with lithium cells, which will fit but have higher voltages and also get rather hot. This is not good for these cameras, so silver oxide G13 cells give the best results for these.

Hi,
Just to amplify on Georges comments, there is a great deal of rubbish talked about batteries (probably spread by people who sell expensive, overpriced adapters!!). The older rangefinders use a simple circuit and adjust the settings by restricting to light into the cell by a variable slit or filters moved by the speed dial modified by the ASA setting which is why these tend to be mounted on the lens body. This type of cct is voltage dependant but can be adjusted either with the adjusting pot or by using a germaniun diode. In this case silver cells must be used.

For SLRs, this type of control cannot be used and so most manufacturers used a "bridge" cct. One side of the cct goes through the cell or cells and the other provides a reference voltage. This reference voltage is adjusted by pots on the ASA and speed dial. The meter gives the difference as an exposure. As the battery supplies the same voltage to both sides of the cct, ant voltage difference is cancelled out. If this were not the case, you wouldn't be able to use alkaline cells in all the MF bayonet Pentax cameras.

For the Spotmatic, I find the best cell to use is the 344 or SR45 (or LR45 for alkaline). There is no real need for rings, adapters or anything else. The wein cells are about £6 whereas the silver cells are about a £1 and last 3 times as long. (the Wein cell is purely a hearing aid battery with 2 holes instead of about 6 or 8 with a collar and costing 10 times as much!) You can get silver replacement cells for the 400 battery but these are just SR45s with a plastic collar and cost about £4. (If you are worried about the collar, you could buy one with and then reuse it!) The 344s are not all that common and the smaller 392 works just as well but is fiddly. I recently bought a card of 40 alkaline cells for 99p. This had 8 392s and 8 LR44s among them.

The important thing to remember is that the mercury 400 cell was made "upside down" in comparison the silver/alkaline cells. With the SR45, the + or case goes in first with the "bump" (-) against the cover.

For the SPF, you can get silver or alkaline 625s but I use the SR44s as I keep these for the K mount cameras and they are a fraction of the cost. I still have a couple of the original mercury cells in both 625 and 400 guise. I have found more difference in the exposure reading between cameras and lenses than I have between the silver and mercury batteries.

Regards
Kim