ste © said:Sorry, this is where my lack of technical knowledge shows. Digital cameras don't have shutters?
No.
Quoted message said:Then what do they have instead?
Nothing, they don't need anything. You can see the picture on the LCD when you aren't taking a
photo, can't you? That's because light is entering the lens and hitting the sensor. This doesn't
happen with a film camera because there's a shutter to prevent the light reaching the film. Only
when you take a photograph does the shutter open to allow light through.
With digital the light is constantly hitting the sensor. When you take a photograph the light
received over a certain period of time is somehow recorded by the camera, processed and stored in
the memory card. I'm not sure how it works exactly, but there's no shutter.
Quoted message said:I can see something closing behind the aperture when I take a photo,
That's the iris in the lens, that's what controls the f-stop. It opens and closes to different
degrees to give you the aperture.
Quoted message said:and I have a shutter speed!
That's what they call it, but it's not a "shutter" speed really, it's just the length of time that
the camera records the light received by the sensor. All these traditional terms are simply being
used to help conventional photographers make the transition to digital. If appropriate digital
terminology were used it would probably confuse a lot of people.
Quoted message said:Also, why not a f1.0 lens? I've seen a f1.2 lens, but I'm not sure what the numbers mean, except
that they are small holes with high depths of field! Is f1.0 so small that it's closed or
something? Or does the scale start at f1.0?
When light passes through a lens, some of it is lost. If no light were lost then it would be an f1
lens. f1 means that all the light is passing through (I'm not sure if anyone's ever managed to make
an f1 lens). f2 means that only half the light is passing through, f4 only a quarter of the light,
and so on. The brighter the lens the more clearly you can see through it, which is an advantage in
dull light. Also, bright lenses tend to be better quality than not so bright lenses. So an f1.2 lens
would be very bright, very good quality and very expensive. An f2 lens is relatively cheap to make.
But that's fixed lenses. Zooms by their nature tend to be darker, so many zooms are only f4. The G3
zoom is f2, which is really very good for a zoom lens.
Quoted message said:I've just looked on his website, but I wasn't sure which ones were taken with the 17mm lens.
Mike? Are you out there?
Quoted message said:Yes, I've noticed that. Even normal shots, and especially portrait format shots, have curved
horizons. Remember that Worms Head shot you put photosig?
Yep. This is due to the cheap lenses used in compacts. Another good reason to get a DSLR with good
quality corrected lenses.
Quoted message said:That's typical from what I've seen (with my shots and other shots too). Best to avoid straight
horizons I think! :o) (nahh, not a chance!)
Best to put the horizon dead centre if you want it straight, or use correcting software later.
Quoted message said:Quoted message said:Quoted message said:(did you read the link I posted to you about the fisheye for the G3?)
No, I must have missed that.
forums.dpreview.comread.aspOpen ↗
Oh, interesting. But to be honest fisheyes have never appealed to me. The only good use I can think
of would be to photograph the entire sky laying on your back, which could be very interesting if the
clouds were.
Quoted message said:So is it basically the same effect as you get from cropping the top and bottom off?
Yes, although it may use some very wide angle lenses. One problem with such ultra ultra wides is
that the edges of the lens are much darker than the centre, so you have to use a correcting filter
to darken the centre. Since the shape of the picture is very narrow, the camera designers can get
closer to the edges of the lens than you could with a normal shaped photograph.
Quoted message said:I seen photos taken with an XPan 2 and they were great. I'm guessing that this is a true
panorama camera?
Is that the Hasselblad? No, that's not a true pano either, just a very wide angle lens. Another
difference is that these types of cameras have conventional lens distortion at the edges, whereas
swing lens cameras don't.
Quoted message said:Early?! Seriously? Ouch! I have been getting up at 6:05am this week, and it's horriffic! Mainly
because I've been going to bed at 2am... :-o zzzzzZZZZZ How come you woke up so early then?
I just went to sleep during the evening.
Quoted message said:I know what you mean about chatting on newsgroups all day! That's why I'm slow at replying to that
Jpegs post below! It takes so long to reply to (as it's such a long post), that I keep putting it
off. I'll reply to your email (with the improved images) at the same time I reply to that post, I
haven't forgotten...
Oh? I had... ;-)
Actually I've wondered about the psychology of this and I think the problem is answering posts in
such a way that requires or encourages a response. Too much of this and the threads grow endlessly.
Better to answer posts without asking new questions or encouraging new comments, if you want to kill
a thread off, or at least reduce the number of posts you have to answer.
Paul
--
The October Project 2003
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