Friday, October 10, 2014

Pentax 6x7 TTL Prism Repair and Exposure Meter Adjustment

The TTL Prism on my Pentax 6x7 camera has a built in exposure meter that was starting to go a bit whacky. The needle would jump all over at random and the view finder area would go black if I tried to use the camera in any position other than the default horizontal position. And it was consistently under exposing everything by 1-1/2 stops.

I decided I would have a go at repairing it and document what I did and hopefully some other folks with similar problems will find this helpful and be able to repair their prism meters also.

First thing you need to do is get the top of the prism off. You will need to have a spanner wrench type tool for removing the top cap screw of the shutter speed dial. I have one of these. I am sure some of you creative folks will make something else work, that is fine.

There are 8 small screws around the outside that you need to remove. 2 of the screws are behind the front name plate so that must be gently pried off to get those 2 screws out.

Here is the front name plate removed and you can see where the 2 screws are located
Gently pry off the front name plate to remove the 2 screws holding the top on

After you remove the 8 screws and the shutter speed dial you can gently tap the edges of the prism top with something soft like a plastic screwdriver handle to get the top to slowly come off.

NOTE: You do not need to remove the on/off button switch to take the prism top off

You should end with this
Note the shutter speed dial spring and washers, don't lose them!

Adjusting the exposure meter when it is off a bit is not to hard, there is one big adjustment screw you can use to correct the exposure needle alignment.

Here you can see the large plastic adjustment screw. I only needed to adjust mine a couple millimeters clockwise to correct the 1-1/2 stop underexposure. Look closely and you can see the black felt pen marks I used to mark the original position and how it is now turned just slightly clockwise.
Large "POTS" adjustment screw for the built in exposure meter

I had 2 more problems though, the meter would go black when I tilted the camera and also the needle was very erratic. Turns out the erratic needle was a loose +6v cable on one of the prism contacts and the meter going black was from the reflecting prism being loose inside the small slot it sits in.

Here you can see the +6v wire that has come loose
Loose +6v wire

Basically I just soldered on another piece of wire and sealed it with some shrink wrap

This next photo is not very good but it is trying to show you the small refective viewfinder prism the meter uses when you look thru the viewfinder. I used some contact cement to glu it back into position. It is the rectangle glass looking thing between the two electrical posts at the bottom of the viewfinder opening.

Here is the top of the meter with the new wire soldered in place and all tucked in ready for assembly. I still need to adjust the exposure first.
Notice the exposure meter and needle assembly on the left

To adjust the exposure meter I just manually triggered the on/off switch with my hand and made several test exposures with different ISO, aperture and speed settings. I used my DSLR in center weighted mode and my Sekonic Auto Studio II light meter as the test metric devices.
Testing the exposure settings
After thorough testing with different ISO, aperture and shutter settings in both bright daylight and dim light at night I feel I have it calibrated it about as good as it can get. It is almost spot on with my DSLR and 90% spot on with my Sekonic. It is one happy prism and exposure meter now!

Happy Prism and exposure meter!

I hope this post will be helpful to anyone else looking to repair their Pentax 6x7 TTL Prism

Tuesday, September 23, 2014

Olancha, Sirretta Peaks and Monache Meadows Southern Sierras Backpacking And Camping Trip

8 days and 7 nights in the great outdoors of the Southern Sierras. We got rained on the second night out and my military bivy kept me dry all night, after that we had sunshine the whole rest of the trip. The Sierra mountains are dry, I mean really dry. The Kern river was not flowing at all thru Kennedy Meadows and many places that normally have a flowing stream were dry or only had pockets of old water. Gary masterminded this trip and we had a great time. I took most of these photos with my Pentax 6x7 MF film camera and the B/W photos were from a rescued 1936 Zeiss Nettar 515 I purchased and repaired the week prior to the trip. I also took my Anba Ikeda 4x5 wooden field camera but only took a single photo of Olancha Peak with it. Fuji Velvia film is great stuff and produces some very vivid colors. Some of the negatives (really transparencies) I purposely scanned the edges of and softened a bit to give them more of a vintage look. My Canon S100 took some of the quick shots needed and inside Packsaddle Cave.

One of our first trips was out to Packsaddle Cave. An interesting site to see for sure, all the stalactites have been broken off and stolen and graffiti on the walls date back to the early 1900's. Trash, clothing, bedding material all are littered about inside the cave. But it is still a neat place to crawl around in and check out. Some of the stalactites are trying to make a comeback though as water continues to seep thru the ceiling of this ancient cave.

Inside Packsaddle Cave
Packsaddle Cave

Some of the stalactites are forming themselves again but I will be dead before they are large
New stalactites forming in Packsaddle Cave
New stalactites forming in Packsaddle Cave
New stalactites forming in Packsaddle Cave

Here you can see the vandalized and broken stalactites. The whole cave is like this and is mostly associated to the early 1900's
Broken stalactites in Packsaddle Cave
Broken stalactites in Packsaddle Cave

The graffiti inside the cave dates from the early 1900's to one day before we were there...people actually go there armed with paint ready to write on the walls. I did not take pictures of any of the large and just sickening stuff, just a few of the really old pencil ones that were way down deep in the cave, the ones where you need to belly crawl to get to
Old graffitti in Packsaddle Cave

There is even "rock art" in the cave..!
Rock Art in Packsaddle Cave

We setup base camp near Big Meadow and explored the Domeland Wilderness area for several days.
One of our day hikes was up to Sirretta Peak. Here is Gary and Joel at the top.
Gary and Joel on Sirretta Peak,. Register is missing

While we never saw any bears we saw lots of tracks and other signs of bears pretty much every day. The trees are great for bears to dig their claws into and they love tearing up signs posted along the trails. I totally forgot to check the trees for any bear fur that may have been stuck in the bark.
Bear Claw marks in the trees

Some great bear scat
Bear Scat, walking stick for size

Bear tracks on almost every trail for miles at a time
Bear Tracks
Bear Tracks
Bear Tracks

Here is some coyote ( I believe) scat fresh on the road as we walked back into camp. The coyotes would howl every night across the meadow.
Guessing Coyote Scat in the road, walking stick handle for size

My fellow hiking companions did not seem to show the same enthusiasm for looking at and analyzing all of the varied animal scat we found.

Several areas we saw deer and large areas showed signs of bedding for them. Here is a good example that shows the legs being bent and the hoove areas
Deer bedding area, you can see the folded legs and hoove impressions

A different day saw us hiking up to Taylor Dome AKA Miranda Dome. Here is Gary ascending the last section that requires some very careful hand and foot placement.
Gary summiting Taylor Dome

From Taylor Dome looking down at Big Meadow. We are camped way past the meadow somewhere near Salmon Creek.
Big Meadow from Taylor Dome

Here are some of my old school film shots of Gary and I on top of Taylor Dome. Olancha Peak is way off in the distance in these photos and is where we would be heading to in a few days as the last part of our trip.
Gary on Taylor Dome. Olancha Peak way off in the distance
Yours Truly on Taylor Dome. Olancha Peak way off in the distance

On our way back to camp we stopped at Salmon Creek. It was pretty much dry as could be with only a few pockets of mosquito water. Gary has been going to this same place for 30+ years and has never seen it dry like this.
Gary checking out the bone dry Salmon Creek

Somewhere on the way to Taylor Dome, the rock climbers have left rope and other climbing stuff all over the faces of this boulder outcrop.
Somewhere near Taylor Dome

Next stop on the trip was to Monache Meadows and Olancha Peak.
Monache Meadows and Olancha Peak in the distance

Here is Gary crossing the Kern River...hardly any water at all!
Gary crossing the almost dry South Kern River in Monache Meadows

Monache Meadows is a big place and was open enough to take some sunset/sunrise photos. We were finally camping someplace where we were not covered by trees. This is Monache Mtn at sunrise. It got down to 20 degrees that night and my water was frozen and my hands quickly became numb as I got up and started taking early morning photos.
Sunrise on Monache Mtn with full moon

Still going with the Fuji Velvia slide film and my old cameras I found the cowboys and cattle rustling around out in the meadow. I love the deep rich colors of the velvia film
Cattle in Monache Meadows

The old 1936 Zeiss folding camera got a chance to photograph the cattle as well. The shutter was frozen shut from the early morning 20 degree coldness on the first shot but freed up for the second. You can see there is a light leak on the top of the photo
Cowboys early in the morning in Monache Meadows

At sunset I setup my 4x5 field camera to take a photo of Olancha Peak. The Fuji Velvia film looks great in person and on a light table. Here is the setup, notice the 7lb Pentax 6x7 camera hanging from the tripod to stabilize the light weight wood camera
Photographing Olancha Peak with the Anba Ikeda 4x5 field camera. Notice the 7lb Pentax 6x7 camera holding the tripod steady
Photographing Olancha Peak with the Anba Ikeda 4x5 field camera. Notice the 7lb Pentax 6x7 camera holding the tripod steady

The composition on the ground glass
Looking thru the ground glass of the 4x5 field camera

And finally the photograph from all of that work. The 4x5 negative from this camera scanned at 9600 dpi is almost 200 megapixels! We would be backpacking to Olancha Peak the next morning.
Olancha Peak at Sundown, Anba Ikeda 4x5 Wooden Field Camera

Our campsite and Monache Mtn in the distance
Our campsite in Monache Meadows. Monache Mtn top right in the sunshine

Olancha Peak standing tall at 12,132'....
Olancha Peak from our campsite

We did a very leisurely 3 day backpack trip up to Olancha Peak from Monache Meadows.
On the PCT going to Olancha Peak

Gary and Joel on the PCT
Gary and Joel on the PCT going to Olancha Peak

Here is a great view from one of my camping spots. That military bivy is one of my best camping purchases ever, it is tough and water/wind proof. Since I carpooled with Gary I packed light (sorta), this was most of my stuff for 8 days.
7 nights with this setup

Here is a photo from the Zeiss camera of the same vista
Looking down into Monache Meadows from our camp spot on the PCT

At the top of Olancha you can see almost everywhere, especially over towards Whitney and Langley
Mt Whitney view from Olancha Peak
Olancha Peak BM
Mt Whitney and others and Gary scrambling on the rocks on Olancha Peak

If you are interested in a full 360 view you can click this image to view and download the original sized photo
360 from the top of Olancha Peak in the Southern Sierra Mountains

It was a great trip!