Well, as Daydreamjay hasn't replied to my suggestions and his further tests how can you know for sure?

Looking at his images, as I said, his problems were likely down to being closer than the minimum distance and hitting the granularity of flash power control at low level (which could, as Rataegeoff mentioned, even be a power control issue failure in the flash itself).

If you want me to examine EXIF too, then feel free to email me an overexposed image and I'll run my eye over it


IMO, I've found the K7 & K5 to be significantly better at flash exposure compared to K10D/K20D

Matt

That's a relief for my wallet

Somewhat academic now... thread

As a moderator I've just updated some of the 'SOLD' signs on the previous page... I was tired of reading through and working out what has gone!! Hope that helps!
Matt

I have both
The 16-45 is much lighter than the 17-70.

Optically, I much prefer the bokeh on the 17-70 (it is very smooth and similar to the 50/1.4 and 24-90). The 16-45 is a bit too busy for me. But that's personal opinion.

The 16-45 zoom mechanism is interesting. It extends at the 16mm end which allows for totally bizarre points of view when used close up. (Pretty fun actually!) The 17-70 is conventional, and has a half decent macro facility.

Of course the 17-70 is SDM only. The focus throw is pretty short, and it can hunt on occasions, but this can be reduced by gently holding the focus rim - to dampen it.

It looks like the 17-70 is partially weather sealed. Not sure how much, but it has the O-ring on the body.

I really like the extra length - the 45-70mm range I use a lot, and I don't miss the 1mm too much at all.

Resolution and contrast on the 17-70 is higher, but the 16-45 is certainly excellent.

It's a tough call... the 16-45 is available at stupidly low prices, but I wouldn't trade my 17-70 (Only possibly for the DA*16-50, but that's another decision!!!)

Matt

There is always a thumbnails embedded in the RAW
If yours showed as separate then you had RAW+JPG enabled on the camera!

The camera uses the thumbnail when scrolling through the images. However, I think once you try and zoom in on the image the camera will load the RAW image data and use that. Of course, you can also try using the in-camera RAW-to-JPG conversion - that will definitely process the RAW data.


Definitely I would copy the card and then work from that. Whenever something is going a bit AWOL you should leave the original well alone. Preferably engage the LOCK on the SD card to prevent anything from writing to it until you've got it resolved (but it may be too late for that already!).

Trying to use the supplied Pentax RAW converter is a good idea.

It might be worth downloading the latest Adobe DNG Converter tool (the stand alone one) and see if it can convert to DNG from the RAW files you have copied from the card. (I think you can do this even though the originals are DNG)

It's certainly possible to recover the embedded JPG from the RAW.

I suppose it's possible that something on your PC has written some data into the PEF/DNG file. Can you let us know computer & OS?

exiftool is one tool.
http://www.sno.phy.queensu.ca/~phil/exiftool/

Matt

My thinking is the 18-135 + 55-300

I had a business trip to Las Vegas and took the 17-70 & 55-300. I did also take the 50/1.4, but in the end I could have left that behind. The 55-300 was very useful for city grab-shots of building details. The 17-70 was the main workhorse. For wider shots I took multiple shots at 17mm and can stitch them together

I would've liked my 12-24 for convenience, but it wasn't a big deal by any means.

The K-5 means that I can leave fast glass behind I've often taken the flash on holiday... and used it perhaps once (if at all!). I don't bother anymore (especially with the K-5!)

Having the 18-135 WR is always a good precaution

Matt

FYI, the Nikon version (which is GPS-only) is £199.99 from SRS. So the Pentax one seems pretty reasonable to me!

Especially as it'll give you up to 5 minute tracking times using a plain tripod. How much do you reckon an astronomical tracking tripod will set you back??

Neat!

I'll be interested to see how it interfaces to the camera though...

Matt

Okay dokay...

I strongly suspect you've hit the minimum flash distance
Looking at the EXIF data I can see that the metering is similar between the two - in some areas the second image is about 1.5Ev higher on the flash-metered readings, but overall there's not much in it.

What I do notice is that you've got the camera on f/3.5, ISO200, 1/180s

Actually, for flash exposure the shutter speed is completely irrelevant! (This is a key piece of understanding for flash work )
The ISO & aperture are what matters.

I haven't got my AF360 to hand, but checking the manual I reckon at ISO200 you have an effective guide number of between 45 and 50. At aperture f/3.5 that's around 13-14.5m maximum distance. The minimum distance is about one tenth - so 1.3 to 1.45m minimum.

You're probably 'on the edge' - where the granularity of flash output is causing you issues. At such a short distance the flash can only control itself so much.

Think of it like putting sugar cubes in your coffee. If you have half a cup of coffee then one cube might be too much, but none is too little.

With all flash systems you'll need to give it some room to work. You can control the effective distance by reducing the aperture (higher f-number), increasing the physical distance, or slugging the output (by using a diffuser that typically cuts output in half). Even a piece of tissue paper over the flash head will do wonders!

The AF360 does show the min & max distances on the LCD display - but, of course, when you angle the flash that disappears (because it doesn't know how high the ceiling/bounce is).


I'd suggest you try exactly the same test:
* With a piece of tissue paper over the flash head
* At f/8 instead of f/3.5
* At double the distance

Once you within the flash range you should get consistently good exposure.

HTH!
Matt

It's because the kit lens doesn't need stopping down
The kit lens doesn't have an aperture ring, and the camera knows about the lens through the digital interface.

With a lens that has no digital contacts (e.g. Pentax K, or M series and M42 stuff) the aperture has to be physically actuated because the camera has no idea what's mounted. It also happens when you use an SMC-F or SMC-FA lens with the aperture ring on anything other than "A".

In fact, you can see it working - if you take the lens off you'll see there's a lever on the left side of the mirror. Pressing the stop down function will make the lever move up.

HTH!
Matt