JPEG/PEF Muddle


malcolmk

Link Posted 13/12/2005 - 11:13
I shot a wedding for a friend yesterday, not my usual thing, and took nearly 350 pictures with the *ist D set on RAW as per usual. Just two of them, the 34th and 35th, have come out as JPEGs. I certainly didn't change to JPEG and if I had done so by accident it's unlikely that I would have fortuitously corrected it a moment later. It doesn't really matter, though I'd have been annoyed if the whole lot had come out JPEG, but I'd be interested if anyone knows how this can happen or if I've missed out on something obvious.

There was another funny thing at at photo 110. I had the camera on 3 second review to keep an eye on any obvious errors and was using the 360FGZ on the camera in P-TTL mode. Four successive shots burnt out completely. Turning off everything and restarting camera and flash fixed things but I'd changed no settings.

Overall the results were good, well if you take 350 shots some are bound to be good! But the events have done nothing to convince me that steering clear of wedding photography is not a good idea.

malcolmk

Link Posted 13/12/2005 - 16:44
I was thinking... Is there an embedded JPEG within a RAW file? My two JPEGs are labelled _MGP0034 etc rather than the usual IMGP. The photos are fine, apart from being JPEGs.

Arthur Dent

Link Posted 14/12/2005 - 00:46
All RAW files embed a jpeg of what the camera thinks would have happened if you were taking a straight jpeg or tiff. I generally ignore them, except maybe to check that I actually got the shot.

RAW processing is an art. Just like the negative was the score, and the print was the performance (according to Ansel Adams), the RAW file is the negative and the final image is the print.

FWIW, I use Adobe DNG converter as the first stage of my intake. That way all metadata is embedded within the file rather than as an xmp sidecar file.
42

malcolmk

Link Posted 15/12/2005 - 15:40
I think you misunderstood me Arthur, my CF card had an uninterrupted sequence of 140 plus photographs, all but two are suffixed PEF. Just the two are labelled JPG. All the data is consistent with having manually switched to JPG and back again, except that I didn't. In fact it's so long since I adopted PEF full time that it took a moment to remember how to make the change.

I conclude that the camera momentarily failed and I shall regard it with some suspicion for a little while.

Don

Link Posted 15/12/2005 - 22:07
You said:
Quote:
Four successive shots burnt out completely. Turning off everything and restarting camera and flash fixed things but I'd changed no settings.

I had that happen too, with built-in flash and 50 1,4 m lens on ist ds2.
The other part about jpegs pefs...I have questions.
1) did you have both pefs and jpegs of same image or jpegs instead of pefs?
2) were you using pentax image lab software or something else?
3) is it possible you converted the file at your pc while it was still in camera? ie.. your pc wrote to the card?
Fired many shots. Didn't kill anything.

malcolmk

Link Posted 17/12/2005 - 15:31
I noticed the problem as soon as I opened the folder to the CF card using Windows Explorer because the latter was set to Details and the file name had been corrupted with a leading underscore character so putting the JPGs at the top of the list. The problem was apparent long before any software utility looked at them.

I had JPGs instead of PEFs (RAW).

Anonymous

Link Posted 17/12/2005 - 16:29
I chalked my overexposed frames to possiblly a sticky diaphram on the old lens. It hadn't been used for a while.

The jpeg thing is weird, any other details? were the images shot during a burst? before or after a battery change...perhaps a full battery discharge, when the batteries were already low, caused the power to drop too low causing a write failure?

Don

Link Posted 17/12/2005 - 16:34
that guest post above was me..sorry.
I meant to say "perhaps after a full flash discharge with weak batteries, causing the power to dip too low, causing a write failure error on the card?"
Fired many shots. Didn't kill anything.

malcolmk

Link Posted 18/12/2005 - 09:34
I see you are as curious as me.

The JPGs were the 34th and 35th out of a total of 356 photographs taken between 2pm and 9pm. The burnt out ones were 110th - 113th after which I turned off and on again.

The camera started with fully charged 2200 mAh batteries, the external flash fully charged 2500s. I did not have to change any batteries during the session and I'm still working on the same charge now.

The lens was the current 16-45 DA zoom thoughout.

I suspect the JPGs are simply a sign of an impending problem with the camera. If it was a software glitch I think we would have read about it elsewhere by now.

Don

Link Posted 18/12/2005 - 14:36
Even if We don't figure it out right now every bit of usefull info will no doubt help someone out in the future, if it is a camera problem.
I shoot up to 18 weddings/year and want to know about such problems. In case I ever have to deal with it.
It could most likely be a bad sector on your mem card causing a read/write error...if that be the case- it'll rear it's ugly head again when your card starts getting full...
ps I'm using 2500mah batteries and getting less to the tank than you are...I swich batteries on my flash when ever the recycle times get a little long.
Fired many shots. Didn't kill anything.

tedwhite

Link Posted 19/12/2005 - 02:23
After reading this discussion with interest, it occurs to me that perhaps you folks could tell me:

1. how many JPEG images I can take before the 1 GB card is full.

2: how many RAW images I can take before the 1 GB card is full.

Also, what are the advantages of downloading the latest Pentax firmware for my *ist DS? Is this latest firmware necessary to shoot RAW?

I'm now in my fouth week with the camera. Initially I was mildly disappointed as images seemed a bit soft and underexposed. The exposure part was easily fixed, not so the softness.

But suddenly I've taken some very sharp pictures (this is all in JPEG as I have yet to try RAW until I get Photoshop CS - I don't think PS 2.0 will do RAW) and have sold a few of them. Huzzah! Perhaps all of this is simply that the camera and I are getting to know one another.

Like it more every day.

Ted

amilner

Link Posted 19/12/2005 - 10:42
Raw on 1 GB - about 90
JPEG on 1 GB - about 300 at highest quality

You don't need the latest firmware to use RAW - just use the quality setting in the shooting menu (the options are 1 2 or 3* or RAW)

If you are going to switch to RAW you may want to get a 3rd party conversion program - the PENTAX one is not very good. I use Capture 1 LE

It is woorth getting the firmware update - it gives the option of continuous AF in the manual and semi automatic modes. It also gives an auto ASA option and an option to use the ML button in manual as a one off Av, Tv or P setting (depending on the option you have chosen in the menu)
Tony Milner
Super A, ME Super, MZ6, K5II, Ricoh GR & lenses from 8-500mm
www.amilner.org www.flickr.com/photos/tonymilner

malcolmk

Link Posted 19/12/2005 - 17:04
Don wrote:
It could most likely be a bad sector on your mem card causing a read/write error...if that be the case- it'll rear it's ugly head again when your card starts getting full...

That's an interesting thought. It was a new Lexar 2GB card and I'd not done much more with it previously than test it worked. I did fill it totally (and another identical one) on the day in question with no further problem. I'll mark the suspect one and report back in the event it happens again.

Don wrote:
ps I'm using 2500mah batteries and getting less to the tank than you are...I swich batteries on my flash when ever the recycle times get a little long.

The flash was beginning to slow down by the very end of the day but by then the important things were done.

tedwhite

Link Posted 20/12/2005 - 01:34
Thank you for your reply, Tony. I know my query was a bit OT, but it seemed, from a read of this thread, that I was in the right place to get an answer or two.

Ted
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