Monday 5 November 2018

Fixing my Pentax K-30 exposure problem: #1 prep

The exposure problem on my Pentax camera has been gradually getting worse.

It is now more likely to produce underexposed images than correctly exposed ones.

So its time to open it up and have a go at fixing it.

(Note: this is part #1 of a 3 part post)

Basically, I  can take (say) two photos under the same conditions, where one is perfectly exposed and the other turns out grossly underexposed.

Both shots taken 1/200th, F6.3 & ISO 200 just a few seconds apart.
The histograms show the huge exposure difference between these photos.

A quick search on the net reveals that this is a common problem with certain models such as the K-30 and K-50. However, Ricoh (the company that now owns the Pentax brand name) don't seem to acknowledge that there is a problem.

I love my K-30, but I'm not prepared to throw good money at it. I bought it in 2012. I expect it would cost at least £150 to fix, and I could probably pick up a second-hand body for about £200 (...or spend my money on something else).

Coincidentally, my wife is thinking about ditching her Pentax K-3 for a mirror-less camera, but I much prefer my K-30 to the higher spec'd (and heavier, slightly larger) K-3. The only thing I envy is the higher resolution (24Mp against my 16Mp).

The aperture problem on my K-30 does not seem to be related to the amount of use. I don't take that many photos. In fact a quick check of EXIF data reveals that I've taken less than 8,000 shots in 6 years. By comparison, my wife has taken over 18,000 shots on her K-3 in just 2 years. This is pretty much in line with the findings of other users; it seems to be age related, rather than usage.

so what is the problem?

According to others, the problem is the miniature solenoid that controls exposure. It appears that the troublesome device has a green body, whereas there is an alternate with a white/clear body which does not appear to give this problem. And it just so happens that some of the earlier Pentax cameras contain this white/clear bodied solenoid.

Pentax K1000 (1979/80), K110D (2006), K-30 (2012) & K-3 (2016)

Fortunately, our collection of Pentax cameras include my old K110D, which has the required solenoid. In this case, it does not control the aperture, it simply opens the internal flash lid. The K110D only has a 6Mp resolution. I bought it in 2006 and have only used it during the last 6 years to photograph the stars, as I'm happy to leave it outside all night.

But I don't want to wreck it, although I'm probably unlikely to use it again.

so what's the plan?

So the plan is to open the K110D and the K-3, remove the good solenoid and swap it with the bad one. Hopefully both cameras will then work OK. Its not a problem if the K110D flash lid does not open 1st time. I almost never use the internal flash on a dSLR anyway!

Pentax K110D & K-30 dSLR cameras

At the moment I'm just doing the prep for this job. The camera body screws are like Phillips cross-heads, but are not the same. They are JCIS (Japanese Camera Industry Standard) screws and require a JIS screw driver, either #0 or #00, I'm not sure which at the moment. But I have both on order from the far east, so this job is going to be on-hold for the next 3-4 weeks until these tools arrive.

why do you keep buying pentax?

I bought the K1000 almost 40 years ago. Having built up a collection of Pentax K-mount lenses, it made sense (when I picked up photography again) to buy a digital Pentax body. Now we have maybe 10 or 11 Pentax lenses and other accessories. We are, where we are.

But I'm not a "brand-bunny".

camera FED Sony Mavica Canon PowerShot A20
More from my camera collection:-
Russian FED-4 (film), 2 Sony digital (i) floppy drive, (ii) CD drive, Canon PowerShot A20 (CF)

The time has come for my wife (who is a proper amateur photographer) to move on. The popularity of digital SLRs is giving way to lighter, mirror-less cameras, although I'm not sure which format (sensor size) will become dominant.

The "micro four thirds" format (m43) seems to be taking off in a big way, despite the relatively small sensor. While the full-frame mirror-less cameras may give higher image quality, most photographers don't print their work on anything larger than A3 paper or crop very small sections out of an image, so may not notice the difference. M43 offers the chance of lighter camera bodies and smaller, lighter lenses. But then APS-C (the current format for dSLR cameras) sits between the two, and may continue to be the most popular size.

If my wife does go down this route, I'll get a chance to play, and maybe I will follow suit. The 2 cameras of interest are the Panasonic Lumix G9 and the Olympus EM1. These manufacturers use the same lens mount, so either one will have the wider choice of Panasonic, Olympus, Leica and (eventually) Sigma lenses. This is a big plus over other manufacturers with dedicated mount types and, therefore, a limited range of lenses.

how to find you shutter count?

Every photo taken on a digital camera includes EXIF data, which may include the current shutter count. The software "exiftool" provides a simple way to view this data.

On Linux navigate to the folder containing a sample photo using file manager. Hit F4 to open a terminal at this location, and type:-

exiftool FileName

...where FileName is obviously the real name of the image file (e.g. mycat22.jpg, Bognor.pef, & so on).

Now look through the data, there is some interesting stuff in there.

The Pentax shutter count only counts manual shutter operation since the last time it was reset by an engineer. For example it does not include "live view" counts and it may have been reset if the camera has been repaired, e.g. you may see something like "Production Code: 8.1 (camera has been serviced)" in EXIF.

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