Is it normal for Pentax ist DS ???

Is it normal for Pentax ist DS ???
Yesterday I bought my Pentax DS. My first (D)SLR camera ever.

When I look through the viewfinder at the bright sky (kit lens is on, camera could be “on” or “off”) it looks like somebody sprayed the glass in the viewfinder with a thousand tiny dark semitransparent dots. You can see through them (they kill say, 30% of the brightness) – but you see them all the time!!! They form some kind of regular pattern – on the corners and sides looks almost like fingerprints (I think it’s not fingerprints though).

I ran to the nearest photostore, checked Nikon D50 – viewfinder smaller, but almost clear. You can see same dot pattern in the corners, but it’s much hurder to see, transparensy like 5%.

I believe you have a dirty viewfinder. You can ask your supplier for a replacement or you can clean it yourself. Search the threads here for cleaning and replacing the viewfinder.

Nols

I believe I have the same thing that you describe, but it is not bad at all. I mean, the VF is still larger and clearer than others I saw. It does look a little bit like fingertips.
--
Peter

Yes, it is normal. The camera I bought was off the display shelf, and I was convinced it was fingerprints. Took it back, the store was happy to exchange. The new one was out of a box....and the same thing. Apparently it is just the type of glass used and has no bearing on the photos.
Grant

it's a plastic piece called the focusing screen. It has a fine matte finish which is extremely delicate. You can replace the screen on the Pentax, but if you try to clean it you may just make it more dirty. Don't use any liquids or solvents to clean it, just a puff of air or maybe an antistatic brush.

You'll know it's dirty if you see black specks of dust on it. Don't worry about dust on the focusing screen, unless it is too much and is really disturbing. Then you can clean it.

The screen is held in by a tray and there is a piece of glass between the screen and the prism viewfinder. This way dust never enters the viewfinder which would be too difficult to clean out.

I think what you are describing is normal. The fine pattern which is engraved in the focusing screen looks like a big fingerprint, and without it you would just see blurred upside down light. I think that screen inverts the light and creates the focused image you see when you look through the viewfinder. It costs about 60$ to replace, just to warn you.
--
Lipo C.
(Lee-Po)
Photography is an art, not a test drive.

I'm no technical guru, but I believe the pattern you are discerning is deliberately etched onto the matte screen to enhance contrast enabling better manual focus. It has sth to do with a fresnell lens or so... Do a search in the forum and you'll find out more.

BTW, I believe that the capacity for using manual focus is one of Pentax's strongs. Only tried manual focus on two non-Pentax DSLRs (C*n*n 300D and 350D), and both were just not right for this. Doesn't make much sense if you cannot use any older manual glass I suppose they're thinking at C*n*n... Fortunately Pentax decided otherwise!

hth, Wim

also check that the dioptre adjustment is set correctly for your eyes.
--
Steve

http://www.pbase.com/steephill

Yes, I adjusted diopter correctly. But still viewfinder seems to be very dusty

Once when my DS was taken from a very cold room into hot humidity, I found condensation inside on the mirror and the focusing screen. Thanks to the condensation I could very clearly make out a partial fingerprint in the top left corner of the screen (as seen thru the viewfinder).

The apparition faded later, but is still visible occasionally when viewing the sky with a lens stopped down quite a bit via the DOF switch Considering where the DS is assembled, this might be a "Filipino phingerprint". My own fingers have never been anywhere near that screen.

And the kit lens comes from Vietnam... no wonder it seems like Ho Chi Minh's revenge :^)

Thanks for everybody who tried to help.
In "DOF preview" mode that pattern becomes much more visible

Still not clear to me - either I've got a very dusty viewfinder with "fingerprints from Fillipines" or it's just matte focusing screen and my imagination.
BTW, in "DOF preview" mode that pattern becomes much more visible.

But dirty or not, it's anyway better than Nikon D50's viewfinder and way better than Rebel's XT.

I plan to have a look at Pentax DS at some other stores - compare their VF, and after I'll make a decision - "To exchange or Not to exchange".
thanks again
PS

You should find that the frostiness of the screen makes it much easier to focus. If it was completely clear and bright, you wouldn't really be able to tell whether the autofocus was putting things into focus or not.

Not a fingerprint from the Philippines, or anywhere else. Assuming you aren't talking about dirt or dust, the regular patter than looks like a fingerprint is called a fresnel lens, which spreads light more evenly to the edges of the viewfinder. Here is a link with some more information:
http://science.howstuffworks.com/question244.htm
From the dictionary:
Main Entry: Fres·nel
Pronunciation: frA-'nel
Function: biographical name

Augustin-Jean 1788-1827 French physicist; instrumental in establishing the wave theory of light; pioneered in use of compound lenses in lighthouses
--
John Power
Racehorse in the Desert

Useful Links to Past Pentax Forum Threads and some Exceptional Images are at: http://www.solutns.com/pages/pentaxforum.html

Don't worry Peter!

Everything is normale. Viewfinder screens always have and had different patterns or a special structure to them. Without that nothing could be projected upon them. There is a reason they used to be called for "matte" screen.

Compare to LCD windows and ask yourself if you want lag and stripes and limited resolution instead. Or have a look thru a cheapo viewfinder camera, the picture is clear and bright and nothing more - there is no infor there for you at all and you can't set focus or check the DOF. Try some film SLR viewfinders and see how they differ from eachother, please also note that noone is totally clear. (Well, there were clear glass "matte" screens produced also, often with a grid etched to them and made for special purpose. Finally see the modern dSLR cameras viewfinders. They also differ. They are made with different goals. If you don't want to check the DOF, or never want to check the autofocus, or never want to use old manual lenses (or new lenses with manual focus), then you might consider another camera. And you won't suffer from thousands of 30% semi permeable spots...

Now I am sure there is a reason you bought a dSLR. The optical viewfinder system is one of the good things that comes with a SLR.

If you decide to keep your SLR I think you once again should check that the diopter setting is in accordance with the user manual. Then try to focus on the optical illusion of a picture instead of upon the "black dots". You should have no problems with this relaxing a little and aim at something else but the sky. When comparing different cameras/viewfinders aim for real things that you would like to have a picture of. Then check the DOF and/or set the focus manually and see what model that works good for you (assuming the lenses are set to the same focal length. Aiming towards the sky with keep you confused and focusing upon the wrong thing.

good luck,

Jonas

racehorse in the desert said:

Not a fingerprint from the Philippines, or anywhere else. Assuming
you aren't talking about dirt or dust, the regular patter than
looks like a fingerprint is called a fresnel lens

Click to expand...

Far be it from me to contradict a racehorse, but I've been familiar with fresnel screens ever since my 2-1/4 square days a loooong time ago. If you can see a fresnel at all, you merely see concentric rings radiating evenly from the screen center.

I've just applied the DOF test looking at a light source with an A-mount lens stopped way down... I do NOT see any central radiating rings, but the grain of the matte focus screen becomes very visible.

In my case, I STILL see not one but two partial fingerprints in the left upper and lower corners (when looking thru the viewfinder). The concave lines of these fingerprints face the screen edge -- which is totally the opposite of a fresnel. Also, the two fingerprints are irregular and dissimilar in shape. There are no fingerprints on the right side of the screen or anywhere else.

Gentlemen, though I'm not with the FBI I can assure you these are partial fingerprints -- and they're not mine.

I suggest the fresnel proponents take a look for themselves at their own screens and prove to themselves you can't actually see any typical concentric fresnel ring pattern, at least on a DS.

2 Pipe Smoker:

I guess we have identical viewfinders. A have grains on the focusing screen, which become more visible in the "DOF preview" mode, and I have something like fingerprintsin in the same corners your Pentax have. I didn't get inside my camera yet and salesmen sworn that nobody opened it before.

May be, it's part of technology in Phillipine? You TAKE the focusing screen by the corners with your two fingers on each corner and DIP it inside the bag with graphite dust for a second.

I like this camera very much and just want to be sure that everything is OK with it. And For sure I gonna keep it - the one i have or the one whith a clearer viewfindeк - if i find it.

Pipe Smoker said:

Far be it from me to contradict a racehorse, but I've been familiar
with fresnel screens ever since my 2-1/4 square days a loooong time
ago. If you can see a fresnel at all, you merely see concentric
rings radiating evenly from the screen center.

I've just applied the DOF test looking at a light source with an
A-mount lens stopped way down... I do NOT see any central radiating
rings, but the grain of the matte focus screen becomes very visible.

In my case, I STILL see not one but two partial fingerprints in the
left upper and lower corners (when looking thru the viewfinder).
The concave lines of these fingerprints face the screen edge --
which is totally the opposite of a fresnel. Also, the two
fingerprints are irregular and dissimilar in shape. There are no
fingerprints on the right side of the screen or anywhere else.

Gentlemen, though I'm not with the FBI I can assure you these are
partial fingerprints -- and they're not mine.

Click to expand...

You are correct. These are matte screens. I am showing my age. Thanks for the compliment though, I am not always right.

So, here is perhaps how it happened:

Worker #1 in Pentax assembly plant, Philippines: "Wow, have you tried that new chicken place down the street? The food is great!
Worker #2: "Yes, but it seemed a bit greasy to me."

Worker #1: "You know, you are right about that. Oh-oh, I forgot to wash my hands after lunch. Well, I have only assembled 12 cameras so far, and those stupid buyers won't know the difference. I'll go wash them now."
--
John Power
Racehorse in the Desert

Useful Links to Past Pentax Forum Threads and some Exceptional Images are at: http://www.solutns.com/pages/pentaxforum.html

racehorse in the desert said:

These are matte screens. I am showing my age.

Click to expand...

I bet my age is bigger than your age :^)

This fingerprint issue reminds me of how folks used to say never buy a Detroit car made on a Monday. I guess this also applies to any *ist-DS made after lunch.

if you take the focusing screen out you will see nothing but blur.
--
Lipo C.
(Lee-Po)
Photography is an art, not a test drive.