Batteries for Nikon FTn

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Shac

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Hi - do any of you use Duracel PX625a alkaline batteries in your Nikon FTn meters and if so does the meter need some calibration?
I know of the CRIS MR9's but am curious about the Duracels.
Thanks in advance
David
 
im not 100% sure how helpful my comment will be but my FTn meter performed perfectly with a button cell battery from Walgreens. i forget the size but im assuming only one type of battery fits it. i forget if it was energizer or duracel but yeah.
 
Shac said:
Hi - do any of you use Duracel PX625a alkaline batteries in your Nikon FTn meters and if so does the meter need some calibration?
I know of the CRIS MR9's but am curious about the Duracels.
Thanks in advance
David
Click to expand...

The problem with alkaline batteries in these heads is that they have a completely different power delivery curve compared to the original mercury cells, which falls further and further from the calibration spec as they age in service. These old meters relied upon the battery not only for voltage but for a specific delivery curve, they didn't have voltage regulators in their circuits. So what happens is that the meter reading can be right on the money some times, and other times well off the mark. Nothing is less useful than an inconsistent meter.

I'm also not certain that the MR-9 battery converter works well in the FTn heads. There are two batteries in series in these heads, I seem to recall hearing that there were issues.

The best course of action is to have the meter circuit re-calibrated to use currently available batteries. Since I re-acquired a Nikon F Photomic FTn last year, I hunted around and found Sover Wong, an F2 specialist. We've only talked about it so far, but he said he could work on F meter heads and provide the same services he does for F2 heads. You can find him at http://www.soverf2repair.webs.com/ ..

(I haven't had mine done as I have been using the plain prism finder and a hand held... :)

G
 
I agree entirely with Godfrey's comments above ^^ his experience/comments match mine from trying out the various options available.

I have dealt with Sover Wong before and he is THE man when it comes to F2's and he will also work on the F and the various meters too. I haven't spoken to him yet regarding my FTn meter but I intend to and I'll send it to him for update/calibration. I'm not sure where the OP is based but don't be put off by distance, Sover is the man that you need to talk to!

Regards,

Simon
 
I have two FTn's converted satisfactorily to using LR44 or SR44 (better) cells available from <battery.adapter@orange.nl>. For a detailed technical treatise on the issue, do a Google search for a pdf document entitled "batt-adapt-US.pdf".

Sorry, got a bit carried away - I converted two Nikkormat FTn CAMERAS with in-built meters, not the FTn meter heads. Same situation really, but I didn't want to mislead anyone. The article I quoted is still valid information, though.
 
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Unless you are shooting color, or a slow contrasty BW like Pan F, the recalibration route is more complicated than necessary IMO. Wein cells are expensive and wear out fast. I have used alkaline 625's in my Nikkormats, Minoltas and Pentax spotmatics for years. I have never felt like I am having exposure problems due to the battery. Because of the extra voltage, they will underexpose slightly so I reduce the ASA setting by about 1/2 stop. As Godfrey says, the output voltage does seem to change over time so you have to watch that, but I have had batteries that are two years old and still give the same exposure readings when measured on a grey card.
 
Many thanks everyone. Based on many of you advising Alkalines I'm giving them a try before going Godfrey's & Flat Twin's routes if necessary (thanks for the info on Sover Wong by the way - I'm in Canada but might have to use him unless I can find some one local (incl US))
David
 
Silver Oxides have a very flat voltage, similar to mercury. It's slightly higher, which might (and might not) require a different ISO setting. Use the sunny f16 rule to check.
 
Godfrey said:
The problem with alkaline batteries in these heads is that they have a completely different power delivery curve compared to the original mercury cells, which falls further and further from the calibration spec as they age in service. These old meters relied upon the battery not only for voltage but for a specific delivery curve, they didn't have voltage regulators in their circuits. So what happens is that the meter reading can be right on the money some times, and other times well off the mark. Nothing is less useful than an inconsistent meter.

I'm also not certain that the MR-9 battery converter works well in the FTn heads. There are two batteries in series in these heads, I seem to recall hearing that there were issues.

The best course of action is to have the meter circuit re-calibrated to use currently available batteries. Since I re-acquired a Nikon F Photomic FTn last year, I hunted around and found Sover Wong, an F2 specialist. We've only talked about it so far, but he said he could work on F meter heads and provide the same services he does for F2 heads. You can find him at http://www.soverf2repair.webs.com/ ..

(I haven't had mine done as I have been using the plain prism finder and a hand held... :)

G
Click to expand...

I was going to answer the original question and talk about Schottky diodes
and who knows what else but what you are telling is very interesting. I have four Photomics plus most of the parts for repairing them but I never found the will to work on them myself and didn't know anyone I trusted. I believed Mr Sover Wong was an F2 specialist only, I will contact him.

Thanks!

GLF
 
I have a CRIS adapter that I have used in my Minolta SR-T bodies, and I have been very happy with it. This thread has me thinking about the alkaline 1.5v 625 batteries, however.

My understanding is that the mercury batteries and the silver oxide batteries provide a steady voltage until the end, when they drop off suddenly. Alkaline batteries, on the other hand, have a long steady decline in voltage.

I would guess that an alkaline battery would have fairly steady output for the duration of a typical amateur photo shoot. In that case, couldn't one test the output of the battery with a VOM (volt-ohm meter) at the time of the shoot and compensate for the existing output at the ISO/film speed dial? The trick would be to know what changes in voltage output correspond to what changes in film speed rating. Has anyone made such determinations?

- Murray
 
The 625As work great. Can't tell the difference when using TRI-X--they're cheap, too--relatively...try them and see what you think.
Paul
 
That's what I did, and I shoot Tri-x 90% of the time so I'll be fine I guess. They were about 3.50 each, so 7 dollars, I'll see what happens.
 
Ok so the batteries are in the meter, and everything works. Using the sunny 16 rule it seems like they're about a stop of, but I can't say for sure. I'll compare it to my F2 meter tomorrow.
 
For some time now I have added 2 schottky diodes in line with the battery wire but recently I got a Nikon F with good working meter and an adapter to hold 2 357 silver oxide cells and re-calibrated the meter to 3.1v. Works good with accurate readings in all lighting situations.

I have another Nikon F on the way and am going to do this fix and see how it works.
 
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