*istD underexposure?

I have used a Ricoh SLR (Pentax lenses) for about 20 years and digital compacts for the last three or four. It's been a long time waiting for someone to bring out a digital body for Pentax lenses but at last it's here.

I ordered a *istD a few weeks ago after reading the generally good reviews.

Unfortunately I was a little disappointed with the results. My impression is that the camera underexposes by 0.5 to 1 stop in the daylight and anywhere from 1 stop to 3 stops using the built in flash. (When compared with results from a film SLR or Fujifilm 6700 digital). This happens in both green and programme modes. If I use RAW mode and boost the sensitivity using the Pentax software by about 1 stop the results are excellent, likewise if I use programme mode and overexpose 1 stop.

I had the camera replaced but am getting similar results with the new one.

Am I doing something stupid or I have I had two dud cameras? I was starting to suspect the former but there are some outstanding photos on the web using standard programme modes.

Any ideas. (Starting to prepare for flames!)

I too have been battling problems with underexposure with my istD. I am not done experimenting yet, but I think I have narrowed my problem down to a certain lens. There are reports of this problem in some reviews on the net. They seem to indicate that it is random in nature. I have only seen the problem with the flash (see Pentax *istD Underexposure with AF360 Flash - Topic). Since we recently had my first grandson I have not had the shutter time I usually do. I hope that I do not continue to see this problem cropping up. I shoot almost exclusively in RAW mode and must boost the sensitivity by 1 stop every time with flash use using the Pentax 28-80 lens. I have not seen this problem in natural light shots (yet?). I know this doesn't help you with your situation but sometimes it's good to know you are not alone.

Hi John U,

Greetings!!

I'm curious if this problem you encountered is consistent.. or could it just be the type of subjects you take (eg. bright backgrounds, something very relfective, etc...) that fools the camera's metering?

I don't know if I'm seeing the same thing as you.... I also own a *ist-D and one thing I noticed about DSLRs in general (I've used Nikon D100, Canon D30, 10D) is that the pics generally seems to appear "dimmer" or about half a stop underexposed compared to how you expect the same shots on film. My Canon/Nikon friends also say the same thing, so like me, they almost always post-process the shots in PS.

With flash, I didn't notice any underexposure, be it the built-in flash in P-TTL or with my AF500FTZ in TTL - with the exception of bounced mode. With the 500FTZ in bounce mode, I always get 1 or 2 stops underexposed.... and nobody has yet able to explain why. I went back to the shop to try another ist-D / 500FTZ units, and same thing happens, BUT NOT WITH THE AF360FGZ - this flash works great!!! even in bounce mode.

I am not sure if there was anything useful with my post
Anyway, I hope somebody else can address your problem with underexposure.


Cheers,

Shotgun

..on many DSLRs to prevent the highlights blowing out in shots with extreme dynamic range. Usually there is enough information in the shot to post process carefully to bring up shadows without affecting highlights.

Having said that I have found the *ist to be accurate outdoors unless there is strong backlighting, in which case the camera underexposes.

Steve

You got it spot-on SetevJ!! That's what I think too.

DSLRs (or digital cameras in general) tends to easily blow away the highlights due to their narrower dynamic range than film, so i think the seemingly 'underexposed' shots is a compensation to prevent this from happening. But take note that there are enough details to work with during post-process. I noticed DSLRs is more capable of capturing details in the shadow areas than film. In a high-contrast situation, I meter more towards the highlights, and then post-process the shadows later without affecting the hghlight details. This can easily be achieved in PS.

Anyways, it is always part of my digital photgoraphy workflow to post-process the shots is PS. I love the feeling of having control over my pics during this stage, although not all of my shots require post-processing. The least I could do is color-correct the images.

We have not used any digital camera yet that presents us with pictures that do not need some sort of treatment in Photoshop. It would seem from this thread that this is not unusual.

Quite a few reviews of the *istD mention that the pictures are initially a little flat and soft until they are adjusted in Photoshop, after which they sparkle with life as expected.

Hi all!

Although I have been one of the main "investigators" of the underexposure and flash issues of the *istD, overall the exposure has been excellent for me

Yes, the images are flatter than consumer digicams. My Canon S30 produces super saturated, full dynamic range images that initially look great, but can be a pain to tweak in PS (blown out highlights especially). The *istD produces lovely images, but like any 'pro' DSLR, there is more control. The consumer cameras are designed for people who probably haven't heard of PS Note that you can adjust the Contrast, Saturation, and Sharpness in the menu of the *istD - which may take you somewhere nearer the consumer output.

So yes, slight underexposure is a good thing in many ways, since CCDs will blow out the highlights. I have found that my workflow is much easier than with the Z1/Fuji Provia/Nikon Coolscan/PS. Generally, I do add a little levels adjustment, curves (to increase contrast or bring out shadows), sometimes a colour-balance adjustment, and some unsharp masking to round it off.

Also, bear in mind that the *istD has two colour spaces - Adobe RGB and sRGB. The default sRGB is intended primarily for screen display, while the Adobe RGB has a different range intended for printing (especially CMYK). If you shoot in Adobe RGB the image will look even flatter on screen, but prints out beautifully. Colour management is another large and great subject you may want to get your head around

All that said, I think there are some firmware issues in exposure control. However, I am confident that the Pentax engineers will hear our voices, investigate, and fix the issues - then all will be even better

In the meantime, it's a good opportunity to brush up some Photoshop skills...

Matt

On further investigation over Christmas (had time to play with it at last) it seems that the underexposure I have been seeing mainly occurs using the built in flash. Daylight shots are generally spot on and shots with my AF330 are very good. The problem starts with the built-in flash - maybe a firmware upgrade will address this at some time in the future?

I've now used the *ist D extensively with the 500 FTG flash and the problem I have is inconsistent exposure---sometimes overexposed a stop or two and other times underexposed a stop or two, and I can't detect a pattern. The only saving grace is that on a digital one can preview to check for exposure and the bracketing works with flash. Many times I find myself shooting manual because the camera's metering simply appears out of sync with the flash or the ttl function is somehow off. Curious because I never experienced this problem on the MZ-S or PZ-1P. I've ordered the 360 FGZ but from the posts, it too has a similar if not as pronounced problem.

Hi all,

Despite all the reports about *ist-D underexposed with flash, I haven't really encountered such problems with direct flash with both 500FTZ and 360FGZ. On a very few occasions, I do get underexposure but on closer look at the images, the causes are easily identifiable, like something highly reflective fooling the metering.

The only exception is when I used the 500FTZ in bounce. The firmware upgrade doesn;t seem to solve this problem too.

Shotgun, you are correct, i forgot to put in my post that I experience the inconstistent exposures almost exclusively when using the bounce function with the *ist D and 500 FTZ combo.

Hi fbphx,

It seems that you are having the same problem I have with my 500FTZ when used with the *ist-D, and it is consistent. I posted this problem here in a separate thread, and in other forums as well, but so far there isn't any solid solution.

I also have tried bringing back my camera and 500FTZ flash back to the shop, tried many other units (both 500 flash and *ist-D), and the problem still exists. I conclude this is a consistent problem with bounce flash on the 500FTZ.

The only workaround I could do is to compensate my shots from +1EV to +2.5EV depending on the subject distance, ceiling height..... more like a guessing game

I don't have this problem with the 360FGZ on normal conditions, but do remember that in any bounce flash phorography, there IS still a potential of getting underexposed shots.

I thought I was the only one getting nuts about the underexposure of the Pentax *istD. On the green, it underexposes by at least 1 stop. I am not sure the whether upgrade firmware is to blame. When I use the built in flash, it also underexposes like crazy. It looks darker than when the flash is off. The pictures are far from when I was using the Minolta 7, 7Hi and A1. The power consumption and versatility of batteries can't be ebat though. And compact too.

Also,when used in wireless mode with the AF360, the strobe focus assist by the built in flash will be annoying when you are covering an event and the camera feelsthat it is dark. use the manula focusing in that case. Or get the cords.

Yes I get the same as I posted yesterday elsewhere on this forum.

The camera is generally fantastic and I could live with the exposure inconsistency.

Installed new firmware and am evaluating. This upgrade was suggested by Pentax UK.

Lawrence

I have also been experiencing tremendous underexposure with my Pentax *ist D when used with flash (built in and Pentax flash) with green and P mode. If I use shutter or aperture-priority, I overexpose it by 1 stop. Now, the camera is in the shop. When using the browser, I noticed that the shoting modes to not correspond. the green comes out as P, the P as Shutter, The shuter as aperture, the aperture priority comes out as Manula, the manual as bulb, the bulb as green. But the pictures are correct. All other info are correct. Then, when I turn it on, the number of shots do not come out as if there is no card inside. Sometimes, the number of shots change even if I did not change the size/quality setting. Eventualy, it comes back to the right number. I change batteries, change the settings and put it back, or change the card until it changes back to the right number. Now, it's with pentax for 2 weeks here in Canada. The last time I turned it on 2 days ago, it kept "pressing the shutter" sound even though I was not pressing the shutter.