Anyone got any views on this camera. It appears to have 15 secs exposure, but it does have 10 megapixels 😮
http://www.dpreview.com/reviews/canona640/ 

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Looks fine to me, but... 15 seconds might not be enough for some shots, but that probably would only apply to big, big chambers, eg north Wales Slate.

I wouldn't worry about the 10 Megapixies, though - they aren't the answer to all of life's problems and in some cases you'll get a better result from a 6 Megapixie camera that a 10 Megapixie one.

It does, of course, fit the bill very nicely for a camera which would do for both underground and overground work and be perfectly portable for holiday snaps and so on. I've now got to the state where I've got three cameras (underground, overground and holidays), which is pretty daft to be honest 😉

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Looks fine to me, but... 15 seconds might not be enough for some shots, but that probably would only apply to big, big chambers, eg north Wales Slate.

I wouldn't worry about the 10 Megapixies, though - they aren't the answer to all of life's problems and in some cases you'll get a better result from a 6 Megapixie camera that a 10 Megapixie one.

It does, of course, fit the bill very nicely for a camera which would do for both underground and overground work and be perfectly portable for holiday snaps and so on. I've now got to the state where I've got three cameras (underground, overground and holidays), which is pretty daft to be honest ;)

Cheers for that info.
Do you think 15 seconds would be ok in largish chamber if I had like a 2,000,000 candle power light?

Cheers

Linden

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Depends how quickly you can shake the torch!

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O I can do that quick enough, hopefully without bluring the image.
Flashes always help as well 😉
Basically what you want is a flash or two, and some people moving around powerfull torches.


linden

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Erm, yes. A small army always helps.

The big benefit of the Nikon 8400 is that you can leave the shutter open for 10 minutes, which means you can make a cup of tea before you have to think about waving torches about :)

The record so far (I think) was set in Moel Fferna with a 2 minute 35 second exposure - and it was needed!

All the same, the majority of pics can be taken inside 15 seconds. Anyway, after a while, the novelty of taking photos of huge chambers wears off and you realise that the best pics are taken in more confined places - just have a look at any of Nimrod's pics and you'll see 😉

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Thanks again 😉
i think perhaps the best way of taking pics of such big chambers is not to flood them with light, but to myteriously light bits of them using flashes to give an idea of scale.

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Depends if you're taking arty shots that you want to enter into a photographic competition 😉

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Dont waste your money, buy something with B (bulb) setting, you will only regret it otherwise!

Would agree with that i have a canon 350D (DSLR) and bulb gets used a lot not just for long exposures!
if you want to travel very light and can fit only one flash in your pack and have no slaves (or if they stop working while 6 hours into a mine which happens fare to often 😞 ) I’ve found its very easy to setup a shot in small space just with one person in frame with a flash fired on "test" or manual while syncing it by simply focusing in turned all lights out, press shutter, fire flash and close shutter, its all handheld but with all lights off (not so good with big parties) the flash burst captures the scene without blurring as is the only light while the shutter is open regardless of how much you move the camera! :o

p.s. the longest exposure I’ve dun UG on base is 6 mins!

The Canon A640 does have a max exposure time of 15 secs. The problem with long exposure times in digital cameras is that sensor noise becomes a problem and the image is degraded. The same applies to increasing the ISO or rating, regardless of how many mega pixels you have. For large open caverns and the like scale, as has been mentioned already in the thread, is important. As we know the tried and tested method of doing this is to mount the camera on a tripod and use your longer exposure time to paint a couple of flashes onto one image in the time you have. But why not keep the camera in the same position and take another or multiple images lighting different parts of the scene. Once the images are loaded to the PC you can use a version of stacking the images in layers and merging/blending said layers to produce a single image. This to me it appears to be the only cost effective way of taking such images as the logistics of humping vast amounts of gear UG seems to me be to be both time wasting and pointless. We live in a digital world, lets use the technology. I'm going to try it anyway as it beats stumbling around a cavern burning your fingers on flash bulbs and getting the film home and processed only to find its not right, yes I remember those days well!!

Increasingly the only differences generally between high end compacts/point and shoot cameras is the reflex view finder and the size of the CCD, the latter being very important for quality images. Manufacturers are tending to get rid of the view finder altogether as the pricing gets evermore competitive. Even the lens situation is got round by using conversion lenses.

Lastly, which do you consider the easiest to use in the dark, viewfinder or LCD screen? Neither is easy but using a LCD screen seems better to me.

I do realize this approach may be a bit anoraky for some but the process is simple considering the lengths photographers went to in the past in darkrooms.

Canon have released another version, A650, which incorporates image stabilsation and a whopping 12 mpixels. And if you are in any doubt as to the quality of such a camera check this out.
http://www.canon-europe.com/Images/13_456157.jpg  or
http://www.canon-europe.com/Images/13_456159.jpg 

There are some stunning photos on this site, which means of course that those who are taking them know what they are doing. :thumbsup:

The Canon A640 does have a max exposure time of 15 secs. The problem with long exposure times in digital cameras is that sensor noise becomes a problem and the image is degraded. The same applies to increasing the ISO or rating, regardless of how many mega pixels you have. For large open caverns and the like scale, as has been mentioned already in the thread, is important. As we know the tried and tested method of doing this is to mount the camera on a tripod and use your longer exposure time to paint a couple of flashes onto one image in the time you have. But why not keep the camera in the same position and take another or multiple images lighting different parts of the scene. Once the images are loaded to the PC you can use a version of stacking the images in layers and merging/blending said layers to produce a single image. This to me it appears to be the only cost effective way of taking such images as the logistics of humping vast amounts of gear UG seems to me be to be both time wasting and pointless. We live in a digital world, lets use the technology. I'm going to try it anyway as it beats stumbling around a cavern burning your fingers on flash bulbs and getting the film home and processed only to find its not right, yes I remember those days well!!

Increasingly the only differences generally between high end compacts/point and shoot cameras is the reflex view finder and the size of the CCD, the latter being very important for quality images. Manufacturers are tending to get rid of the view finder altogether as the pricing gets evermore competitive. Even the lens situation is got round by using conversion lenses.

Lastly, which do you consider the easiest to use in the dark, viewfinder or LCD screen? Neither is easy but using a LCD screen seems better to me.

I do realize this approach may be a bit anoraky for some but the process is simple considering the lengths photographers went to in the past in darkrooms.

Canon have released another version, A650, which incorporates image stabilsation and a whopping 12 mpixels. And if you are in any doubt as to the quality of such a camera check this out.
http://www.canon-europe.com/Images/13_456157.jpg  or
http://www.canon-europe.com/Images/13_456159.jpg 

There are some stunning photos on this site, which means of course that those who are taking them know what they are doing. :thumbsup:

Hello!
Thanks for your comment! Firstly your method of layering the images sound affective, though I have not yet got the software!
LCD is definatly better. With viewfinder you often have to put yourself into strange positions depending on the height of the tripod. It's also difficult to see (being dark) and you annoyingly have to move torches around etc... whilst looking through the view-finder.

!Mucho gracies!

Linden

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