MFlenses - A new life in a digital age
MFLenses 2026

Manual Focus Lenses Forum

Explore the world of vintage lenses through repair notes, real test shots, and detailed archive threads packed with images.

Explore the world of vintage lenses through repair notes, real test shots, and detailed archive threads packed with images.
logovectorizer.com
Spotlight

Featured partner placement for the forum front page.

Gave my Asahi Pentax Spotmatic-F an outing with Colorplus
Post new topic Reply to topic
View previous topic :: View next topic  


Post
Posted: Sun Oct 12, 2025 12:43 pm
Post subject: Gave my Asahi Pentax Spotmatic-F an outing with Colorplus
Reply
Post
Posted: Sun Oct 12, 2025 12:43 pm
Post subject: Gave my Asahi Pentax Spotmatic-F an outing with Colorplus
Reply
I gave my Asahi Pentax Spotmatic-F Gift Camera an outing with a 1.5 V battery to see how it performed instead of the Mercury 1.35 V
I loaded with 2005 dated kodak Colorplus 200 found in my film fridge and processed in 'well-used' C41 ---
24mm f3.5 SMC Takumar



50mm f1.4 SMC Takumar


28mm f3.5 SMC Takumar


Post
Posted: Sun Oct 12, 2025 10:02 pm
Post subject:
Reply
Post
Posted: Sun Oct 12, 2025 10:02 pm
Post subject:
Reply
Like 1

The old Kodak film is stil usable!


Post
Posted: Mon Oct 13, 2025 12:03 pm
Post subject:
Reply
Post
Posted: Mon Oct 13, 2025 12:03 pm
Post subject:
Reply
1.5 Silver oxide batteries work great in the SP-F. I havent seen a significant difference under normal shooting conditions


Post
Posted: Tue Oct 14, 2025 1:32 am
Post subject:
Reply
Post
Posted: Tue Oct 14, 2025 1:32 am
Post subject:
Reply
If I recall correctly the Spotmatic F metering circuit is "balanced" -- the voltage difference make no difference in exposure readings.

Very nice film results! Takumar colors pair well with the Kodak film too.


Post
Posted: Wed Oct 15, 2025 12:53 pm
Post subject:
Reply
Post
Posted: Wed Oct 15, 2025 12:53 pm
Post subject:
Reply
visualopsins wrote:
If I recall correctly the Spotmatic F metering circuit is "balanced" -- the voltage difference make no difference in exposure readings.

Very nice film results! Takumar colors pair well with the Kodak film too.

A long long time ago, in a galaxy far away there was the Spotmatic yahoo-group
Among the gems that came out of it was a document about the batteries for the Spotmatic.
I cant attach the pdf, but says this about the SPF:

Quote:

SP F.
• Mallory PX625, Duracell PX625A, Excel Z625PX, Eveready E-625N.
• The Spotmatic F uses a dual coil meter movement that, like the
bridge circuit, cancels out battery voltage variations on the
level we are dealing with here. So it is immune to the
difference between 1.35v and 1.5v, too. The original battery
for the Spot F was a mercury type. In this case, Pentax used
the identical circuit in the KM and K1000, without any
electronic changes. They substituted the silver types with NO
ALTERATION at all.


My SPF belonged to my father in law, he bought it new in 1974 or 75 and the battery compartment is for SR44


Post
Posted: Tue Oct 21, 2025 4:43 am
Post subject:
Reply
Post
Posted: Tue Oct 21, 2025 4:43 am
Post subject:
Reply
Beautiful photos! Thank you for sharing!


Post
Posted: Tue Oct 21, 2025 5:16 pm
Post subject:
Reply
Post
Posted: Tue Oct 21, 2025 5:16 pm
Post subject:
Reply
@ pentaxpete: Thank you for sharing these images !! -

@ titrisol: I wasn't aware of the "stabilized" circuit of the Spotmatic; that's a very useful information indeed - especially since my Minolta SR-T cameras really need mercury batteries ...

S


Post
Posted: Sun Apr 19, 2026 3:49 am
Post subject:
Reply
Post
Posted: Sun Apr 19, 2026 3:49 am
Post subject:
Reply
Looks like a very sharp lens!
Post new topic Reply to topic
Page 1 of 1