| Author | Thread |
|
|
10/31/2005 08:22:35 PM · #51 |
Originally posted by dwterry:
Originally posted by greatandsmall:
Make sure you are clothed before taking a picture of a reflective object! |
This one sounds like the voice of experience! |
LOL. I caught myself doing this the other day. Fortunately, I have a heightened sense of awareness due to images I have seen (on this site and others). A guy sells stuff on ebay with naked reflecions in the objects. And someone here did a tribute to the image. Forgive me for not remembering who it was. Funny Stuff! |
|
|
|
10/31/2005 08:23:18 PM · #52 |
Originally posted by Nullix:
I haven't heard of twice your focal length, I've only heard of it being your focal length (remembering digital crop). That would make a 50mm lense having a min speed of 1/50th sec or 1/60th unless it's at 1.6 scensor then it would be 1/80th or which ever is the closest increment. |
I tend to doubt the effect of the "digital crop" on this one.
If it were a "magnification of the image" (like throwing a 1.4x TC on the camera) then I would agree. Any movement of the lens would be magnified 1.4 times.
But a crop is just that ... by using a smaller sensor you simply capture a smaller portion of the same image as would have hit the back of the camera. So there is no magnification of the movement of the lens...
Anyway, that's *my* current thinking on the subject. :-) |
|
|
|
10/31/2005 08:23:46 PM · #53 |
Originally posted by greatandsmall:
Originally posted by dwterry:
Originally posted by greatandsmall:
Make sure you are clothed before taking a picture of a reflective object! |
This one sounds like the voice of experience! |
LOL. I caught myself doing this the other day. Fortunately, I have a heightened sense of awareness due to images I have seen (on this site and others). A guy sells stuff on ebay with naked reflecions in the objects. And someone here did a tribute to the image. Forgive me for not remembering who it was. Funny Stuff! |
I think it was Konador (Ben). But when I went to find the teapot pic I couldn't.... Anyone have that "coming of age" link? |
|
|
|
10/31/2005 08:24:46 PM · #54 |
Originally posted by greatandsmall:
LOL. I caught myself doing this the other day. |
I'm just curious... what were you photographing in the buff?????
|
|
|
|
10/31/2005 08:37:07 PM · #55 |
Originally posted by dwterry:
I'm just curious... what were you photographing in the buff????? |
Oh boy...now I've started something! I don't wear pajamas to bed. I woke up, got on the internet and for some reason, felt compelled to post a picture of the inside of my RV/Home (which contains numerous reflective surfaces). That picture did not make it onto the internet, and NO, I will not share it...shame on you people;) It's been erased. |
|
|
|
10/31/2005 08:39:44 PM · #56 |
Originally posted by greatandsmall:
Originally posted by dwterry:
Originally posted by greatandsmall:
Make sure you are clothed before taking a picture of a reflective object! |
This one sounds like the voice of experience! |
LOL. I caught myself doing this the other day. Fortunately, I have a heightened sense of awareness due to images I have seen (on this site and others). A guy sells stuff on ebay with naked reflecions in the objects. And someone here did a tribute to the image. Forgive me for not remembering who it was. Funny Stuff! |
Konador made the parody. |
|
|
|
10/31/2005 09:03:32 PM · #57 |
Originally posted by dwterry:
Originally posted by Nullix:
I haven't heard of twice your focal length, I've only heard of it being your focal length (remembering digital crop). That would make a 50mm lense having a min speed of 1/50th sec or 1/60th unless it's at 1.6 scensor then it would be 1/80th or which ever is the closest increment. |
I tend to doubt the effect of the "digital crop" on this one.
If it were a "magnification of the image" (like throwing a 1.4x TC on the camera) then I would agree. Any movement of the lens would be magnified 1.4 times.
But a crop is just that ... by using a smaller sensor you simply capture a smaller portion of the same image as would have hit the back of the camera. So there is no magnification of the movement of the lens...
Anyway, that's *my* current thinking on the subject. :-) |
I think I would agree with this...just think of it this way... If you shot with a 100 mm lens on a 35 mm slr, you'd need to shoot 1/100 of a second or faster. If you took your print in a darkroom and cropped it to the size a digital sensor records at, the center wouldn't be any sharper than the edges. If there was camera shake, I would think it would be evident throughout the whole image equally. |
|
|
|
10/31/2005 09:15:47 PM · #58 |
Originally posted by bear_music:
ALWAYS USE YOUR LENS HOOD!
|
Alas, I have lost mine, and I'm too cheap to order a new one...
|
|
|
|
10/31/2005 09:18:09 PM · #59 |
Originally posted by faidoi:
Konador made the parody. |
Link? (Honestly, I can't find that excellent image!) |
|
|
|
10/31/2005 09:26:17 PM · #60 |
|
|
|
10/31/2005 09:28:09 PM · #61 |
| Beware of security guards - every photographer is automatically considered a terroist. |
|
|
|
11/01/2005 09:55:58 AM · #62 |
Originally posted by greatandsmall:
Originally posted by dwterry:
I'm just curious... what were you photographing in the buff????? |
Oh boy...now I've started something! I don't wear pajamas to bed. I woke up, got on the internet and for some reason, felt compelled to post a picture of the inside of my RV/Home (which contains numerous reflective surfaces). That picture did not make it onto the internet, and NO, I will not share it...shame on you people;) It's been erased. |
I smell a 'Nude Reflections in Household Crap' challenge!!
|
|
|
|
11/01/2005 10:58:41 AM · #63 |
Originally posted by bear_music:
Those two rules of thumb are the "inverse rules":
1. Shutter speed hand-held should be the inverse of the focal length of the lens, or faster. (1/100 is the inverse of 100) It's correct that you need to take into account the crop factor, as noted earlier.
Robt. |
The 'crop factor' should be irrelevant to shooting speed and lens focal length. The amount of motion blur is precisely the same whether the image is cropped or not. That said, if you enlarge the image sufficiently, the motion blur will become more apparent! |
|
|
|
11/01/2005 11:26:58 AM · #64 |
Originally posted by dwterry:
Originally posted by Nullix:
I haven't heard of twice your focal length, I've only heard of it being your focal length (remembering digital crop). That would make a 50mm lense having a min speed of 1/50th sec or 1/60th unless it's at 1.6 scensor then it would be 1/80th or which ever is the closest increment. |
I tend to doubt the effect of the "digital crop" on this one.
If it were a "magnification of the image" (like throwing a 1.4x TC on the camera) then I would agree. Any movement of the lens would be magnified 1.4 times.
But a crop is just that ... by using a smaller sensor you simply capture a smaller portion of the same image as would have hit the back of the camera. So there is no magnification of the movement of the lens...
Anyway, that's *my* current thinking on the subject. :-) |
Look at it this way: Imagine you are handholding the camera and your camera shake, from your trembling hands, is going through .1 degree of arc, up and down. (I realize this is extreme, it's just to illustrate the point) Further imagine you're using a wide angle lens that covers 100 degrees of angular view. Your shake is covering a thousandth of the image arc. Now suppose you're using a lens that covers ten degrees of angular view; your shake is covering a hundredth of the image arc.
That's clear, right? You need a faster shutter speed with a "longer" lens because the angular component of the shake is a much larger percentage of the angular width of the picture. This is very evident if you try to hand-hold an actual telescope, where you lierally cannot hold it centered on a distant object, you simply have to have a tripod.
Now, if you were to take the wide-angle picture and CROP it to the same framing as the telephoto image, then that .1 degree of shake would cover the same angular percentage of the image as it did in the actual telephoto shot, and the camera movement is more noticeable on the cropped WA shot than it is on the uncropped shot.
The reason you need a faster shutter speed to handhold a longer lens is that the angular movement of the unstable camera is a greater percentage of the angular coverage of the image, and this effect is exactly mimicked by cropping in on whatever image you have taken; the tighter the crop, the more noticeable is the movement.
If this were not true, then camera shake would be less of a factor on P&S cameras at full zoom than it is on dSLR cameras with the equivalent telephoto mounted, and I can tell you from personal experience that this is not the case.
R.
Message edited by author 2005-11-01 11:31:46.
|
|
|
|
11/01/2005 12:02:15 PM · #65 |
| Exactly right, Bear. The absolute amount of blur remains constant, but the percentage of blur increases as the image is cropped. |
|
|
|
11/01/2005 12:07:57 PM · #66 |
Thanks, Bear, for your very detailed explanation. I understand it a lot better now.
|
|
|
|
11/01/2005 12:09:28 PM · #67 |
Originally posted by ElGordo:
Exactly right, Bear. The absolute amount of blur remains constant, but the percentage of blur increases as the image is cropped. |
Correct. And the perceived "softening" of the image is a function of the percentage of blur. To visualize this, imagine shooting a point source of light against a black background with a wide angle lens. The full frame shot might seem to show a sharp point of light, but as you crop further and further in it will become more and more obvious the light's not quite sharp. That's the telephoto effect of magnifying the blur.
Robt.
|
|
|
|
11/01/2005 12:10:03 PM · #68 |
Doesn't it also depend on viewing distance? If you stand 3 feet away from your two test images, wouldn't the blur cover the same percentage of the total area visible to the eye of the viewer?
I think part of the apparent increase in blur on the cropped image has to do with viewing it at closer range, so that it fills the same area of the visual field as the original image. |
|
|
|
11/01/2005 12:14:05 PM · #69 |
Biggest thing I always need to remember is to reset the camera to a more standard setting before putting it away for the night. Let's say I'm out shooting in manual mode with a high ISO and very low shutter speed and put my camera away and forget about it. The next day I see something that I need to get a real quick shot of and grab the camera, focus and click... I end up with a blown out shot as my camera was still set for the night before.
-danny
|
|
|
|
11/01/2005 12:18:22 PM · #70 |
Does the size and resolution of the sensor matter in addition to the cropping issue bear music mentioned? That is, will a sensor with smaller pixels be more sensitive to camera shake than a sensor with larger pixels?
And more importantly, how does the "equation" change because of this? Or is this difference trivial compared to the variation between what length/speed any two people can handhold?
Message edited by author 2005-11-01 12:21:51. |
|
|
|
11/01/2005 12:19:17 PM · #71 |
Originally posted by GeneralE:
Doesn't it also depend on viewing distance? If you stand 3 feet away from your two test images, wouldn't the blur cover the same percentage of the total area visible to the eye of the viewer?
I think part of the apparent increase in blur on the cropped image has to do with viewing it at closer range, so that it fills the same area of the visual field as the original image. |
Well, the discussion is ignoring pixelization, which certainly contributes to the degradation of the cropped image. But try the following experiment:
If you have a tripod that has a tilt scale marked in degrees, set up a wide-angle shot of a landscape and shoot it twice. For the second shot angle the camera downwards 1 degree. Do the same with a telephoto shot of the same landscape. Now in photoshop superimpose the two images on each other, each at 50% opacity. The full-frame WA shot will look sharper than the telephoto shot.
Now crop the superimposed WA shot to match the framing of the telephoto shot. Ignoring pixelization, they will be indistinguishable, basically. This works better if you do it with moderate wide angle and a "short" telephoto, so the pixelization doesn't get extreme as the WA shot won't have to be cropped grotesquely.
R.
|
|
|
|
11/01/2005 12:20:33 PM · #72 |
Originally posted by hankk:
Does the size and resolution of the sensor matter in addition to the cropping issue bear music mentioned? That is, will a sensor with smaller pixels be more sensitive to camera shake than a sensor with larger pixels? |
Perhaps in theory (I don't honestly know) but the practical effects will be minuscule.
R.
|
|
|
|
11/01/2005 01:07:31 PM · #73 |
Originally posted by GeneralE:
... Most people say never use the built-in flash unless you are desperate and have no alternative. |
This may have been true in the past but, along with so many other things, is changing as modern electronics technology marches forward. Today's built-in flashes are more useful than they used to be. But still not as good as an external flash attachment. And even the best flash lighting is still going to be inferior to natural sunlight.
|
|
|
|
11/01/2005 01:16:28 PM · #74 |
Originally posted by coolhar:
Originally posted by GeneralE:
... Most people say never use the built-in flash unless you are desperate and have no alternative. |
This may have been true in the past but, along with so many other things, is changing as modern electronics technology marches forward. Today's built-in flashes are more useful than they used to be. But still not as good as an external flash attachment. And even the best flash lighting is still going to be inferior to natural sunlight. |
I have yet to see a built-in flash that doesn't suck.
I'd crank the ISO to 3200 and underexpose before I'd use one. They are too close to the lens axis to do anything but create red-eye, a harsh shadow and generally unflattering light. They might be useful to give some fill, but they still suck.
|
|
|
|
11/01/2005 02:09:32 PM · #75 |
Originally posted by Spazmo99:
I have yet to see a built-in flash that doesn't suck.
I'd crank the ISO to 3200 and underexpose before I'd use one. They are too close to the lens axis to do anything but create red-eye, a harsh shadow and generally unflattering light. They might be useful to give some fill, but they still suck. |
From the dpreview.com review of the 20D--
"Higher pop-up flash
The EOS 20D now has a flash which raises considerably higher than the EOS 10D, it now has a claimed FOV coverage of 17 mm. It also uses E-TTL II flash metering which utilizes lens distance information to improve flash power calculation."
"Internal flash
The EOS 20D features an all new E-TTL II pop-up flash, which raises much higher than the EOS 10D's unit which means fewer problems with lenses causing a shadow and will probably improve red-eye performance. The internal flash has a guide number of 13 (approx. 3.3 m @ 17 mm / 2.3 m @ 85 mm; ISO 100) and a wide angle coverage of 17 mm. Support for E-TTL II means that lens distance information is now used to calculate the required flash power. Flash sync speed is up slightly to 1/250 sec.
The EOS 20D also allows for FE-Lock (Flash Exposure Lock) which can be used to take a meter reading of the subject using the flash before taking the shot. This can be useful for recomposing the scene, with the flash up (or an EX flash attached) simply aim the center of the frame at the subject to be metered, press the * button and the camera will fire the flash and take a meter reading, the next shot you take will use this locked exposure."
From the imaging-resources.com review of the 20D --
"The new flash pops up higher than the flash on the 10D, offering greater clearance over lenses and also somewhat reducing the likelihood of red-eye at closer ranges. Unlike the Digital Rebel, which has a similar pop-up mechanism, the new mechanism doesn't rattle noticeably when the camera is moved, and it pops up more quietly as well. The 20D gives you a great deal of control over flash exposure, allowing you to adjust flash and ambient exposure independently of each other, in one-half or one-third EV increments. This makes it very easy to balance flash and ambient lighting for more natural-looking pictures. The 20D also uses E-TTL II control for both the built-in and compatible external flashes (according to Canon this includes the current 550EX flash, as well as the new 580EX), a new standard that promises better, more balanced exposures."
From the dpreview.com review of the E-500--
"Pop-up Flash
Thanks to the height of the viewfinder prism and a nice long arm the E-500's pop-up flash sits a better than most 53 mm (2.1 in) above the top of the lens, this is about the same as the Canon EOS 350D (Digital Rebel XT). This additional height will be very useful when using lenses with their hoods attached and should also help avoid red-eye. The pop-up flash is now released electronically (either via a push-button or automatically if in the right mode), it has a guide number of 13 and an X-sync speed of 1/180 sec. In a low light situation with the flash raised the camera will strobe the flash to act as an assist lamp for the AF system (it must be raised manually to perform this function)."
From the dpreview.com review of the FZ30 --
"The pop-up flash is activated manually by a small switch on its left side (viewed from the rear). It is fairly high - around 1.5 inches from the top of the lens barrel, which should help minimize red-eye, and fairly powerful. With auto ISO you can use the flash from around 30cm to 7m, and it recycles very quickly. All the usual flash options (on, off, red-eye reduction, slow synch) are available; the red-eye reduction system is a simple single pre-flash (around 0.8 seconds before the main exposure)."
From the dpreview.com review of the PowerShot S2 IS --
"The pop-up flash on the S2 IS is a little more powerful than the unit used on the S1, and sits a little higher (meaning red-eye is even less of a problem)."
From the dpreview.com review of the Fuji S9000 --
"The pop-up flash is manually released (using a button on right side). It sits fairly high, which helps minimize red-eye, and there's a very efficient AF illuminator just below, which allows focus in almost complete darkness at distances of up to around 3m."
|
|
Home -
Challenges -
Community -
League -
Photos -
Cameras -
Lenses -
Learn -
Help -
Terms of Use -
Privacy -
Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 08/07/2025 01:17:20 PM EDT.
