*istD Underexposure/Pentax Repair

About 1 1/2 months ago I posted here stating that I was sending my *istD and accessories into Pentax USA for repair due to underexposure problems. Many of you replied that you were having the same problems while others gave help and guidance on how to work around the issue. Thank you to all who wrote to help! As promised, I mentioned that I would write back with what happened in my dealings with Pentax. (I tried to find my original post for your reference but the "my postings" feature of this site is apparently not up right now.) Long story short. . . Pentax agreed with me that my camera was underexposing as I described but they could not fix it. They were working with the engineers in Japan to fix the problem, but ultimately thought that it was taking too long so they agreed to send me a brand new camera. While I felt that the repair took too long, you can now count me as a very happy Pentax *istD user as the camera and flash now work perfectly. The new camera validates that I have made a good choice by going with Pentax. If you are a fellow *istD user who is fighting this issue of underexposure (2-3 Stops), stop! Send it back and get it fixed or replaced. It's an awesome camera when it is working correctly.

Randy

Randy, I had exactly the same experience with yours but my last *ist D only typically underexpose by 0.5 to 1.5EV for different lenses. What the main mystery is that why Pentax local service centers cannot rectify and locate the cause of the problem? I just wonder..

--
Best Regards,

RiceHigh - A 16-year User of Pentax AF SLR System (My Equipment are listed in Profile)

Hi there,

Thanks for sharing. I was a little surprised when Pentax said that they couldn't fix the camera. The truth is probably somewhere in the middle. A tech at Pentax USA told me that they could identify/duplicate the problem and that they were in contact with Pentax Japan to help solve it. The tech indicated that they were close to finding a solution but that it was taking too long so they opted to send me a new unit. I have some mixed feelings about the service that I received from Pentax USA. I still feel that 1 1/2 months to repair/replace a camera is too long. (Hire more technicians if you have that large of a backlog.) The flip side is that they finally did what was right and got me taken care of. Note that towards about the 4th week I was calling them every day asking about the status of my repair. I think that they got tired of me calling. Works great now.

Randy

p.s. The guy at Pentax is named Mark Davis and he seems to be a great guy and he really tried to help. All of the people at Pentax were polite and caring. The dealer where I purchased the camera said that Pentax was the best of the manufacturer's that he dealt with. He implied that if I had purchased a Nikon or Canon I would not have been able to speak with anyone and would have had to wait at least 6-8 weeks to get my camera back. Probably true.

RiceHigh said:

Randy, I had exactly the same experience with yours but my last
*ist D only typically underexpose by 0.5 to 1.5EV for different
lenses. What the main mystery is that why Pentax local service
centers cannot rectify and locate the cause of the problem? I just
wonder..

--
Best Regards,
RiceHigh - A 16-year User of Pentax AF SLR System (My Equipment are
listed in Profile)

Click to expand...

Rascati said:

Hi there,

Thanks for sharing. I was a little surprised when Pentax said that
they couldn't fix the camera. The truth is probably somewhere in
the middle. A tech at Pentax USA told me that they could
identify/duplicate the problem and that they were in contact with
Pentax Japan to help solve it. The tech indicated that they were
close to finding a solution but that it was taking too long so they

Click to expand...

Is this something that would be fixed in a new firmware update do you (or the tech) think?

Also, is there a way to tell if your camera is underexposing? I've seen some of mine seem to need a bit more brightness, but I'm not sure if it's just my eyes / monitor / thinking it's lighter than it is or what? Is there a set up that you can use to determine if it's underexposing a bit or a lot or is this something that you have to have the eyes of an experienced photographer to see?

TIA

alan

arcterex said:

Rascati said:

Hi there,

Thanks for sharing. I was a little surprised when Pentax said that
they couldn't fix the camera. The truth is probably somewhere in
the middle. A tech at Pentax USA told me that they could
identify/duplicate the problem and that they were in contact with
Pentax Japan to help solve it. The tech indicated that they were
close to finding a solution but that it was taking too long so they

Click to expand...

Is this something that would be fixed in a new firmware update do
you (or the tech) think?

Also, is there a way to tell if your camera is underexposing? I've
seen some of mine seem to need a bit more brightness, but I'm not
sure if it's just my eyes / monitor / thinking it's lighter than it
is or what? Is there a set up that you can use to determine if
it's underexposing a bit or a lot or is this something that you
have to have the eyes of an experienced photographer to see?

TIA

alan

Click to expand...

1-2 stops would be pretty obvious! Make sure your monitor is calibrated. Also, most SLRs expose to preserve highlights so they tend to look underexposed when there are bright areas in the image. This only happens in matrix mode.
Steve

*isteve said:

arcterex said:

Rascati said:

Hi there,

Thanks for sharing. I was a little surprised when Pentax said that
they couldn't fix the camera. The truth is probably somewhere in
the middle. A tech at Pentax USA told me that they could
identify/duplicate the problem and that they were in contact with
Pentax Japan to help solve it. The tech indicated that they were
close to finding a solution but that it was taking too long so they

Click to expand...

Is this something that would be fixed in a new firmware update do
you (or the tech) think?

Also, is there a way to tell if your camera is underexposing? I've
seen some of mine seem to need a bit more brightness, but I'm not
sure if it's just my eyes / monitor / thinking it's lighter than it
is or what? Is there a set up that you can use to determine if
it's underexposing a bit or a lot or is this something that you
have to have the eyes of an experienced photographer to see?

TIA

alan

Click to expand...

1-2 stops would be pretty obvious! Make sure your monitor is
calibrated. Also, most SLRs expose to preserve highlights so they
tend to look underexposed when there are bright areas in the image.
This only happens in matrix mode.
Steve

Click to expand...

Thanks Steve I am pretty sure mine isn't 1-2 stops bad, but it might be a little underexposed. With PSCS I generally bump by .9 ev to get the image nice and bright, but that could be just my preference. I'll try some experimenting though to see if I can set up a proper controlled test.

My camera underexposes by around 2 stops when used at wider angles with the 16-45mmDA It is fine with the Pentax 50 1.4 and Sigma 105mm

Do I have the same problem? I read other people had problems with underexposure when being used with the wide angle lens.

Joe

RiceHigh said:

Randy, I had exactly the same experience with yours but my last
*ist D only typically underexpose by 0.5 to 1.5EV for different
lenses. What the main mystery is that why Pentax local service
centers cannot rectify and locate the cause of the problem? I just
wonder..

--
Best Regards,
RiceHigh - A 16-year User of Pentax AF SLR System (My Equipment are
listed in Profile)

Click to expand...

A can of worms has just been opened.........

jcapasso said:

Joe

RiceHigh said:

Randy, I had exactly the same experience with yours but my last
*ist D only typically underexpose by 0.5 to 1.5EV for different
lenses. What the main mystery is that why Pentax local service
centers cannot rectify and locate the cause of the problem? I just
wonder..

--
Best Regards,
RiceHigh - A 16-year User of Pentax AF SLR System (My Equipment are
listed in Profile)

Click to expand...

Click to expand...

jcapasso said:

My camera underexposes by around 2 stops when used at wider angles
with the 16-45mmDA It is fine with the Pentax 50 1.4 and Sigma
105mm
Do I have the same problem? I read other people had problems with
underexposure when being used with the wide angle lens.

Click to expand...

The EV readings of my 16-45 is usually 0.5EV faster than my 43 Limited and the pictures often appear to be darker than the 43. Nevertheless, both seems to be acceptably exposed. The 24-90 is somehow close to the 16-45 for the whole range too.

BTW, I suspect Pentax has encoded some data into the lens such that those high contrast lenses like 16-45, 24-90 would have to "under" somehow to avoid highlight wash-out. For lenses which are able to reproduce the finest greys, exact exposure value can be used (my 43's EV readigns agree with my FA*85 too)

p.s. I have tired to use +0.3EV compensation and found that sometimes obvious highlight blow-out occurs and thus I now leave my camera at 0EV even when using the 16-45.

--
Best Regards,

RiceHigh - A 16-year User of Pentax AF SLR System (My Equipment are listed in Profile)

hugnut said:

A can of worms has just been opened.........

Click to expand...

Have to agree with you, more like a bucket of worms.

I could join in, panic and start imagining that my *istD must have this dreaded ailment requiring Pentax service.

Reading any list of symptoms it is easy to conclude that yes I also have those symptoms, OH my, am I sick too!

But, let's do this one step a time and save a lot of time and inconvenience.

I have underexposed shots too, but when I examine them calmly, I see the camera was trying to save the highlights, all DSLR's do this so that is not a fault.

I have also compared readings between the *istD exposure meter and 2 different Gossen lightmeters I know work correctly.

All 3 light meters are fooled the same way by non standard or difficult lighting, what is more important all 3 are very close to agreement on exposure.

The key issue is that the repaired *istD in question was underexposing by about 2 stops, fairly extreme underexposure.

I have never had underexposure that severe, so that is the key issue in determining if you may have a fault worth following up.

Severe underexposure, not just a bit of underexposure.

An interesting test or experiment is to take the same shot using all 3 *istD metering modes and comparing them.

Or dial in say 0.7 exposure compensation take some shots, when I did this I found some overexposed, so clearly it is not a fault that always underexposes, just metering that requires some input from a human.

Back to taking more pictures.

And lets not forget the "sunny 16 rule..."

With 100 speed film in bright sunlight at 1/100th of a second you should get a "proper" exposure at F16.

So at iso 200 in bright sunlight at 1/200th of a second you should have a "proper" exposure at F16.

If you go outside in bright even, average, sunlight and you ist D is telling you 1/500th second at F16 at iso 200 then something is very wrong.

2 stops under is easy to tell if you have a problem, basically almost all of your pictures would suck...

(For anyone who is worrying there is something wrong with their camera.)

I had a similar case with my pop up flash failing when I was using it as a controller in conjuncton with the 360 fgz.

The Pentax agents here in New Zealand sent the camera back to Japan because they couldn't find the fault, but sent me a completely new camera about a month later saying it was irrepairable.

I was delighted of course, but I'm a little cautious now about using it with flash.

Regards,

Max...Auckland NZ

every camera I've owned in the last 35 years has had similar problems. I have 13 lenses ranging from 12mm to 500mm, when they are pointed at a grey card that fills the frame they all give readings within 1/3rd of a stop of each other when compared to a Sekonic studio meter, when used in "real life" they can vary by up to 2 stops. Where exposure is critical I use a handheld incident light meter or use the "sunny 16" rule.

All reflected light meters, no matter how sophisticated, suffer from "subject failure" and always will, the only time to worry is when the grey card test gives an answer that is obviously wrong. The one advantage of digital is that you can immediately view the histogram and make appropriate corrections.

Last Sunday I was taking pictures in Bath Abbey and had to vary the exposure compensation between -1.3 to + 1.7 to get the effect that I wanted but I regard this as normal in difficult lighting where there are large amounts of transmitted light (incident light readings useless) and deep shadows (reflected light useless).
dave

[email protected] said:

I had a similar case with my pop up flash failing when I was using
it as a controller in conjuncton with the 360 fgz.

The Pentax agents here in New Zealand sent the camera back to Japan
because they couldn't find the fault, but sent me a completely new
camera about a month later saying it was irrepairable.

I was delighted of course, but I'm a little cautious now about
using it with flash.

Regards,

Max...Auckland NZ

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