All Forum Comments
Comment by George Lazarette posted on Bounce type flashgun at 10/07/2007 - 09:13
Quote:
And presumably, the flash-sensor cuts off the flash when it's measured a total amount of reflected light, returning to it from whatever its field of view happens to be.
If there's a significant amount of light returning to the flash sensor from an area outside the camera's angle of view, is it not possible that what remains inside the camera's angle of view will be therefore be underexposed?
If so, then
Incidentally, I realise that using a shorter focal length won't change the duration of the flash in this instance, and therefore the part of the frame that looked dark before won't get any more light.
But with more of what comes back to the flash sensor now contributing to the picture, the bright bits from the previously cut off part will look bright, and presumably appropriately so in relation to the dark bit that was in the frame before.
I suppose the only way to fix this is the way they do with more sophisticated guns - focus the beam from the flash more, so that it comes back from a smaller area.
I do take your point that if the illumination is uneven, then the sensor and the lens could be picking up different intensities of light. My point was that, in general, the focal length and image frame are immaterial.George Lazarette wrote:
The sensor is a light meter, and it measures the light, then cuts off the power to the flash.
Indeed.The sensor is a light meter, and it measures the light, then cuts off the power to the flash.
And presumably, the flash-sensor cuts off the flash when it's measured a total amount of reflected light, returning to it from whatever its field of view happens to be.
If there's a significant amount of light returning to the flash sensor from an area outside the camera's angle of view, is it not possible that what remains inside the camera's angle of view will be therefore be underexposed?
If so, then
Quote:
The focal length of the lens and the size of the camera sensor are immaterial.
cannot be true, since it's the focal length of the lens and camera sensor size that determine the camera's angle of view.The focal length of the lens and the size of the camera sensor are immaterial.
Incidentally, I realise that using a shorter focal length won't change the duration of the flash in this instance, and therefore the part of the frame that looked dark before won't get any more light.
But with more of what comes back to the flash sensor now contributing to the picture, the bright bits from the previously cut off part will look bright, and presumably appropriately so in relation to the dark bit that was in the frame before.
I suppose the only way to fix this is the way they do with more sophisticated guns - focus the beam from the flash more, so that it comes back from a smaller area.
G
Comment by George Lazarette posted on Bounce type flashgun at 10/07/2007 - 09:09
Quote:
The sensor is a light meter, and it measures the light, then cuts off the power to the flash. The focal length of the lens and the size of the camera sensor are immaterial.G wrote:
Please elaborate Quote:
I came to the tentative conclusion that the angle of view seen by the sensor could, if the lens focal length was too long, be too great, and therefore respond to more reflected light than gets in through the lens.
Is this likely to be right?
No.I came to the tentative conclusion that the angle of view seen by the sensor could, if the lens focal length was too long, be too great, and therefore respond to more reflected light than gets in through the lens.
Is this likely to be right?
G
Comment by George Lazarette posted on Bounce type flashgun at 10/07/2007 - 08:18
Quote:
I was getting a few underexposed shots until I noticed that if I zoomed the lens out a bit, the exposure was fine.
I came to the tentative conclusion that the angle of view seen by the sensor could, if the lens focal length was too long, be too great, and therefore respond to more reflected light than gets in through the lens.
Is this likely to be right?
No.George Lazarette wrote:
Funnily enough, I have had the most consistent results on digital cameras using old auto-sensor flashes like the AF240Z. One was sold on Ebay today for under a tenner.
I've been experimenting a bit with an old auto-sensor flash - the Braun 320 BVC. It has bounce and swivel, but no zoom. And only one pin on the bottom. Nevertheless, I measured its trigger voltage at only about 8V, so I've gone ahead and used it on the K10DFunnily enough, I have had the most consistent results on digital cameras using old auto-sensor flashes like the AF240Z. One was sold on Ebay today for under a tenner.
I was getting a few underexposed shots until I noticed that if I zoomed the lens out a bit, the exposure was fine.
I came to the tentative conclusion that the angle of view seen by the sensor could, if the lens focal length was too long, be too great, and therefore respond to more reflected light than gets in through the lens.
Is this likely to be right?
G
Comment by George Lazarette posted on Bounce type flashgun at 09/07/2007 - 23:24
Quote:
Yes, Pentax AF540FGZ or AF360FGZ. If you want it to work properly, buy Pentax. There is a Sigma (something like DG500) that has had good reports. Just about any old Pentax fit flash gun will work fine in manual mode, but you need to do more work to get the exposure correct.
Funnily enough, I have had the most consistent results on digital cameras using old auto-sensor flashes like the AF240Z. One was sold on Ebay today for under a tenner.Yes, Pentax AF540FGZ or AF360FGZ. If you want it to work properly, buy Pentax. There is a Sigma (something like DG500) that has had good reports. Just about any old Pentax fit flash gun will work fine in manual mode, but you need to do more work to get the exposure correct.
If budget is an issue, that's a good way to go.
G
Comment by George Lazarette posted on Bounce type flashgun at 09/07/2007 - 22:07
Kemal,
I like these from a compositional standpoint, especially numbers one and four. The model is attractive and relaxed, and the pictures look less "snapped" (ie: more considered) than some of your previous submissions.
However, all of your shots do have an amateurish quality about them. These look rather like the first efforts of somebody who has just learned to use a darkroom.
It may be that this is deliberate, and if so, fair enough. However, I find my enjoyment is somewhat marred by the feeling that they could be processed better.
In your shoes, I would spend some time improving my post-processing skills, which in my view lag behind your talent for composition.
G
PS: Numbers 2 and 4 should be reduced in size a bit to avoid people having to scroll to see them.
I like these from a compositional standpoint, especially numbers one and four. The model is attractive and relaxed, and the pictures look less "snapped" (ie: more considered) than some of your previous submissions.
However, all of your shots do have an amateurish quality about them. These look rather like the first efforts of somebody who has just learned to use a darkroom.
It may be that this is deliberate, and if so, fair enough. However, I find my enjoyment is somewhat marred by the feeling that they could be processed better.
In your shoes, I would spend some time improving my post-processing skills, which in my view lag behind your talent for composition.
G
PS: Numbers 2 and 4 should be reduced in size a bit to avoid people having to scroll to see them.
Comment by George Lazarette posted on Girl in a Black Dress / Critiques Please at 10/07/2007 - 07:49
Quote:
Thanks guys. Tryin not to be a pain in the a__.
I hope not, that's somebody else's job.Thanks guys. Tryin not to be a pain in the a__.
Try this:
http://www.bdimitrov.de/kmp/macro/index.html
G
Comment by George Lazarette posted on Favorite Pentax "ODD" lens? (Image) at 20/07/2007 - 10:15
Quote:
It's looking as if niblue has disappeared somewhere and is totally unaware of this win, which of course delays our next challenge.
I'll wait until Wednesday evening and then I think we'll carry on with another competition. Hopefully niblue will return, but we shall see.
And PeteKD has disappeared too, at exactly the same time. Is there a connection? Enquiring minds want to know.It's looking as if niblue has disappeared somewhere and is totally unaware of this win, which of course delays our next challenge.
I'll wait until Wednesday evening and then I think we'll carry on with another competition. Hopefully niblue will return, but we shall see.
G
Comment by George Lazarette posted on Weekly Competition #2 - Play at 17/07/2007 - 21:43
Welcome back, Viewfinder, and with a proper camera and a decent picture, too! Congratulations.
G
G
Comment by George Lazarette posted on Weekly Competition #2 - Play at 15/07/2007 - 13:03
Quote:
To someone who is used to handling guns, that picture is extremely uncomfortable to look at..
Lee
Those who question the usefulness of the tethered shooting facility, now have an answer.To someone who is used to handling guns, that picture is extremely uncomfortable to look at..
Lee
G
Comment by George Lazarette posted on Weekly Competition #2 - Play at 11/07/2007 - 17:14
I suppose the only way to fix this is the way they do with more sophisticated guns - focus the beam from the flash more, so that it comes back from a smaller area.
Best of all, by far, is full manual, where you do test shots to determine precisely the right exposure. However, in a dynamic situation, this isn't always practicable.
G