http://luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml
http://www.slrnikond50blog.com/
You can use the histogram to check if the exposure was correct.
When you review a picture and pull up the histogram, you’ll usually see a pattern that resembles a bell curve. If that curve is squished to the left of the screen, you’ve underexposed – a lot of shadow areas will be completely black. And if the curve is squished to the right of the screen, you’ve over-exposed – a lot of highlights are completely white.
If a portion of the histogram touches the top that means the highlights are blown out.
The common advice is to ‘expose to the right’. That means to expose the shot so that the curve is as far as possible to the right of the box, without actually blowing any highlights.
So take care to adjust the exposure so that the histogram doesn’t touch either of the sides or the top of the histogram doesn’t touch the top of the screen.
Here’s more on the reasoning behind that: http://luminous-landscape.com/tutorials/expose-right.shtml
Musings by Dr Aarti
Wednesday, April 28, 2010
BOREKH
http://www.daifukusensei.com/?page_id=52
Brenizer Method
Bokeh consists of the out-of-focus highlights seen in photographs. You know, those beautiful little balls of light that just seem to pop off the screen and make a picture look so much sexier? Here’s an example. So it follows that a bokehrama is a panorama — or a series of shots — of bokeh, lots of blur, and a single subject in focus. The best way to describe it is to showcase a terrific example, one from kick-butt wedding photog Ryan Brenizer, from whom I’ve learned this method:
http://www.flickr.com/photos/carpeicthus/3554480740/
Free substitute for Autostitch
http://hugin.sourceforge.net/
http://www.philmalpas.com/pages/artcomp.asp
Brenizer Method
Bokeh consists of the out-of-focus highlights seen in photographs. You know, those beautiful little balls of light that just seem to pop off the screen and make a picture look so much sexier? Here’s an example. So it follows that a bokehrama is a panorama — or a series of shots — of bokeh, lots of blur, and a single subject in focus. The best way to describe it is to showcase a terrific example, one from kick-butt wedding photog Ryan Brenizer, from whom I’ve learned this method:
http://www.flickr.com/photos/carpeicthus/3554480740/
Free substitute for Autostitch
http://hugin.sourceforge.net/
http://www.philmalpas.com/pages/artcomp.asp
Friday, April 23, 2010
FOCAL LEnght and Point and Shoot Zoom
The zoom factor like e.g. the 10X you mentioned above is simply the
longest focal lengt divided by the shortest focal length of that lens.
It could be 10mm-100mm or 20mm-200mm or 100mm-1000mm. All of those
lenses would be a 10x zoom.
The zoom factor does not tell you anyting about the magnification (or
tele) factor. That can be expressed in e.g. 8x, too. This is commonly
used in e.g. binoculars where 7x is a common marine magnification, 8x or
10x a common terrestial magnification, and 15x a strong glass for e.g.
bird viewing. For photography however it is much more common to use the
focal length. Problem is that the magnification not only depends on the
focal length but also on the sensor size.
On a full-frame sensor a focal length of 50mm is considered a 'normal
lens'. A 200mm lens would have a 4x magnification, a 1000mm lens a 20x
magnification.
For a DX sensors you have to adjust the magnification factor for the
smaller sensor size by a factor of 1.5 or 1.6, depending on the actual
camera.
Ok, going back to your original question: a 200mm lens on a DX body
(Canon EOS Digital Rebel XTI) will have a magnification(!) factor of
200/50*1.5 = 6x.
And it will have a zoom(!) factor of 1 because is is not a zoom lens to
begin with.
If it were e.g. a 50-200mm lens, then the magnification factor would be
1.5x - 6x and the zoom factor 4x on a DX body.
On a full frame camera this lens would have a magnification factor of
1x-4x and still the same zoom factor of 4x.
Oh, one more note: neither the camera nor the lens determines the image
size. The image size only depends on how you print it.
longest focal lengt divided by the shortest focal length of that lens.
It could be 10mm-100mm or 20mm-200mm or 100mm-1000mm. All of those
lenses would be a 10x zoom.
The zoom factor does not tell you anyting about the magnification (or
tele) factor. That can be expressed in e.g. 8x, too. This is commonly
used in e.g. binoculars where 7x is a common marine magnification, 8x or
10x a common terrestial magnification, and 15x a strong glass for e.g.
bird viewing. For photography however it is much more common to use the
focal length. Problem is that the magnification not only depends on the
focal length but also on the sensor size.
On a full-frame sensor a focal length of 50mm is considered a 'normal
lens'. A 200mm lens would have a 4x magnification, a 1000mm lens a 20x
magnification.
For a DX sensors you have to adjust the magnification factor for the
smaller sensor size by a factor of 1.5 or 1.6, depending on the actual
camera.
Ok, going back to your original question: a 200mm lens on a DX body
(Canon EOS Digital Rebel XTI) will have a magnification(!) factor of
200/50*1.5 = 6x.
And it will have a zoom(!) factor of 1 because is is not a zoom lens to
begin with.
If it were e.g. a 50-200mm lens, then the magnification factor would be
1.5x - 6x and the zoom factor 4x on a DX body.
On a full frame camera this lens would have a magnification factor of
1x-4x and still the same zoom factor of 4x.
Oh, one more note: neither the camera nor the lens determines the image
size. The image size only depends on how you print it.
Wednesday, April 21, 2010
APERTURE
http://www.digital-slr-guide.com/maximum-aperture.html
1 – Natural Light Photos
No flash with a max aperture of f/2.8
A digital SLR camera sensor needs light to create an image.
There are two ways that it can get the light that it needs: it can keep the shutter open for a long period of time or open the aperture as wide as possible.
Let's say that you hate taking photos with flash, because you know how washed out they look.
You're indoors and your camera tells you that with your aperture set to f/4, your shutter speed will have to be 1/30 of a second. That's not going to be fast enough to take a shot of your child rampaging in the living room.
You're going to have to use the flash, or get the kid to sit VERY still.
If you had a lens with a maximum aperture of f/2.8 (which lets in double the amount of light of f/4) then you can use a shutter speed of 1/90, which means that you can get clear photos without the flash
2 – Fast Shutter SpeedsA fast shutter prevents motion blur
You're taking photos on an overcast day of a flower in the backyard. A strong breeze is blowing, and that flower is moving all over the place.
You set the aperture on your lens as wide as it can go (let's say f/5.6), and check the shutter speed. The camera tells you that you can use a shutter speed of 1/125 of a second.
That's not fast enough to get a clear photo of the flower. You're stuck.
If you had a lens with a wider maximum aperture you could get the shot. With a wider aperture (say f/2.8) your shutter speed could be 1/500 of a second.
Since the wide aperture lets in so much light, the shutter doesn't have to stay open as long.
3 – Reduced Depth of FieldWide aperture = shallow depth of field
Lenses with wide maximum apertures have shallow depth of field.
Without getting into a discussion on depth of field (that could take awhile), I will just refer to the photographic example at right.
This shot was taken with a lens set to f/3.2. Notice that the background is completely out of focus even though the ball in the foreground is clear?
This is shallow depth of field.
Nature and portrait photographers use this all the time to reduce the impact of a busy background.
If you have a lens with a maximum aperture of f/5.6, you can't reduce the depth of field as much as you can with a wider aperture.
1 – Natural Light Photos
No flash with a max aperture of f/2.8
A digital SLR camera sensor needs light to create an image.
There are two ways that it can get the light that it needs: it can keep the shutter open for a long period of time or open the aperture as wide as possible.
Let's say that you hate taking photos with flash, because you know how washed out they look.
You're indoors and your camera tells you that with your aperture set to f/4, your shutter speed will have to be 1/30 of a second. That's not going to be fast enough to take a shot of your child rampaging in the living room.
You're going to have to use the flash, or get the kid to sit VERY still.
If you had a lens with a maximum aperture of f/2.8 (which lets in double the amount of light of f/4) then you can use a shutter speed of 1/90, which means that you can get clear photos without the flash
2 – Fast Shutter SpeedsA fast shutter prevents motion blur
You're taking photos on an overcast day of a flower in the backyard. A strong breeze is blowing, and that flower is moving all over the place.
You set the aperture on your lens as wide as it can go (let's say f/5.6), and check the shutter speed. The camera tells you that you can use a shutter speed of 1/125 of a second.
That's not fast enough to get a clear photo of the flower. You're stuck.
If you had a lens with a wider maximum aperture you could get the shot. With a wider aperture (say f/2.8) your shutter speed could be 1/500 of a second.
Since the wide aperture lets in so much light, the shutter doesn't have to stay open as long.
3 – Reduced Depth of FieldWide aperture = shallow depth of field
Lenses with wide maximum apertures have shallow depth of field.
Without getting into a discussion on depth of field (that could take awhile), I will just refer to the photographic example at right.
This shot was taken with a lens set to f/3.2. Notice that the background is completely out of focus even though the ball in the foreground is clear?
This is shallow depth of field.
Nature and portrait photographers use this all the time to reduce the impact of a busy background.
If you have a lens with a maximum aperture of f/5.6, you can't reduce the depth of field as much as you can with a wider aperture.
Tuesday, April 20, 2010
CCD Cleaning
http://www.bythom.com/cleaning.htm
If you've got a D3s, D60, D90, D300, D300s, D700, or D5000, regularly use the built-in dust cleaning mechanism. About once every shooting session and after any long period of disuse should be fine. Remember to hold the camera normally (sensor perpendicular to the ground) so that the dust falls to the adhesive strip at the bottom of the sensor chamber designed to catch the dust. Skip to Step 3.
(For those without a built-in shake dust removal system) On a regular basis, use your blower bulb to try to dislodge casual dust from the filter surface (camera should be facing down so that dust dislodged falls out of the camera through the lens mount). Do this in a clean environment and regularly, and you generally will get most of the dust dislodged this way without having to touch the filter.
Use a Sensor Brush whenever you need to remove casual dust the automated cleaning or blower bulb can't dislodge. Follow their procedures exactly; don't take shortcuts. Most of the time, this is enough cleaning to remove the offending dust. If you're traveling, you can use an Arctic Butterfly for this step, but be extremely careful not to touch it to the sides of the sensor mounting frame.
If a Sensor Brush session doesn't remove stubborn dust, use a Sensor Swab wet with Eclipse or Dust Aid Ultra Clean solution. Again, follow the manufacturer's procedures exactly.
If you still have a persistent dust bunny, you'll probably have to really wet a Sensor Swab (being careful not to wet it so much that the cleaning material breaks) and go over that spot again, perhaps with a gentle scrubbing action. This will likely leave streaks. If it does, let the sensor dry and then do another regular Sensor Swab of the sensor. Sometimes you have to do this sequence several times (wet pollens are no fun to remove).
If you've got a D3s, D60, D90, D300, D300s, D700, or D5000, regularly use the built-in dust cleaning mechanism. About once every shooting session and after any long period of disuse should be fine. Remember to hold the camera normally (sensor perpendicular to the ground) so that the dust falls to the adhesive strip at the bottom of the sensor chamber designed to catch the dust. Skip to Step 3.
(For those without a built-in shake dust removal system) On a regular basis, use your blower bulb to try to dislodge casual dust from the filter surface (camera should be facing down so that dust dislodged falls out of the camera through the lens mount). Do this in a clean environment and regularly, and you generally will get most of the dust dislodged this way without having to touch the filter.
Use a Sensor Brush whenever you need to remove casual dust the automated cleaning or blower bulb can't dislodge. Follow their procedures exactly; don't take shortcuts. Most of the time, this is enough cleaning to remove the offending dust. If you're traveling, you can use an Arctic Butterfly for this step, but be extremely careful not to touch it to the sides of the sensor mounting frame.
If a Sensor Brush session doesn't remove stubborn dust, use a Sensor Swab wet with Eclipse or Dust Aid Ultra Clean solution. Again, follow the manufacturer's procedures exactly.
If you still have a persistent dust bunny, you'll probably have to really wet a Sensor Swab (being careful not to wet it so much that the cleaning material breaks) and go over that spot again, perhaps with a gentle scrubbing action. This will likely leave streaks. If it does, let the sensor dry and then do another regular Sensor Swab of the sensor. Sometimes you have to do this sequence several times (wet pollens are no fun to remove).
Nikon focus modes
When you set your camera lens to AF (auto focus), digital SLR camera's offer the photographer a choice between interchangeable modes. Auto focus modes can vary between different digital camera brands. In the past, Nikon's two most popular modes were called Continuous Servo AF and single area AF. Nowadays, they are called AF-C (short for auto focus continuous) and AF-S (short for auto focus single). Many Nikon models also have AF-A and MF (manual focus) modes to choose from as well.
What are the differences between AF-C, AF-S, AF-A and MF focus options?
AF-C (AF continuous, sometimes called continuous servo) is good use when photographing moving objects. When your camera is set to AF-C and you focus on a moving subject, for example a dog running towards you, the focus will stay on the animal so long as your shutter button is held half way down. In other words, the camera will keep re-focusing as the animal moves. That is, so long as you keep your shutter button held half way down.
AF-S (AF single, sometimes called single area AF) mode, is good for photographing subjects that don't move, such as flowers or portraits etc. It locks the focus on the non moving object that you want to photograph. You can then recompose the shot and take the photograph.
AF-A is where the camera selects and goes between the last two modes. If it thinks the subject you are photographing is stationary, then it will automatically use AF-S focus mode. If it picks up that the subject you're photographing is a moving subject, then it will automatically use AF-C focus mode. This is also the default camera focus mode, unless you change the setting to AF-C or AF-S.
MF is the manual focus mode. It's unclear why this focus mode is included, because nowadays there is usually an option to switch between auto and manual focus on the side of the actual lens. Maybe it's in case you come across a lens that doesn't give you that option.
Why would photographers change between focus modes?
The default camera setting is AF-A. As mentioned earlier, this mode guesses if the subject you are photographing is stationary or moving, and accordingly sets the focus to either AF-C or AF-S. Photographers don't always trust the camera to pick the correct setting, preferring to make the choice themselves.
http://www.slrphotographyguide.com/camera/nikon-digital-slr/focus-modes.shtml
What are the differences between AF-C, AF-S, AF-A and MF focus options?
AF-C (AF continuous, sometimes called continuous servo) is good use when photographing moving objects. When your camera is set to AF-C and you focus on a moving subject, for example a dog running towards you, the focus will stay on the animal so long as your shutter button is held half way down. In other words, the camera will keep re-focusing as the animal moves. That is, so long as you keep your shutter button held half way down.
AF-S (AF single, sometimes called single area AF) mode, is good for photographing subjects that don't move, such as flowers or portraits etc. It locks the focus on the non moving object that you want to photograph. You can then recompose the shot and take the photograph.
AF-A is where the camera selects and goes between the last two modes. If it thinks the subject you are photographing is stationary, then it will automatically use AF-S focus mode. If it picks up that the subject you're photographing is a moving subject, then it will automatically use AF-C focus mode. This is also the default camera focus mode, unless you change the setting to AF-C or AF-S.
MF is the manual focus mode. It's unclear why this focus mode is included, because nowadays there is usually an option to switch between auto and manual focus on the side of the actual lens. Maybe it's in case you come across a lens that doesn't give you that option.
Why would photographers change between focus modes?
The default camera setting is AF-A. As mentioned earlier, this mode guesses if the subject you are photographing is stationary or moving, and accordingly sets the focus to either AF-C or AF-S. Photographers don't always trust the camera to pick the correct setting, preferring to make the choice themselves.
http://www.slrphotographyguide.com/camera/nikon-digital-slr/focus-modes.shtml
Metering
Metering means to ensure that u properly expose ur scene. There are 3 kinds of mode (a) matrix metering (b) centre weighted (c) spot metering
(a) matrix metering - normally used in landscape photography to properly expose the whole scene, the camera will determine the light across the whole picture and try to find the best setting to properly expose everything.
(b) centre weighted - normally used in portrait setting or other scenes where there is a main object that occupies abt 70% of the picture center. The camera will try to properly expose the 70% of that picture and "ignore" the background. So for example, if ur object is black and ur background is white, the camera will meter the black object, and will try to adjust itself to bring out the black object's details. In order to do so, it got to expose more. So wat u get is a properly exposed black object against a over exposed background. Remember the background is already white, and because of the need to expose more to bring out the black details, the white background will be overexposed.
So i think u get wat i mean, the camera will only care abt the center 70%.
(c) spot metering - similar to the centre weighted metering, but just that in spot metering, we meter only a small spot eg. a 6mm diameter circle in the picture. This is used for example, when there is a small frog in a bright picture. if u use matrix metering, the camera will evaluate the whole scene and think that the whole picture is too bright, and hence under expose the picture to generate a proper exposure for the whole scene. But in doing so, the small frog may be further underexposed and become dark frog.
in addition, if u use centre weighted metering, remember it assigns abt 70% to the center of the picture, but the frog is only very very small in the picture! hence the end result will also be the camera feels that the scene is too bright and underexpose.
Thus in spot metering, u aim the center crosshair on the frog to meter the frog. This will ensure that the frog is properly exposed and be seen! but of course the background may not be properly exposed
(a) matrix metering - normally used in landscape photography to properly expose the whole scene, the camera will determine the light across the whole picture and try to find the best setting to properly expose everything.
(b) centre weighted - normally used in portrait setting or other scenes where there is a main object that occupies abt 70% of the picture center. The camera will try to properly expose the 70% of that picture and "ignore" the background. So for example, if ur object is black and ur background is white, the camera will meter the black object, and will try to adjust itself to bring out the black object's details. In order to do so, it got to expose more. So wat u get is a properly exposed black object against a over exposed background. Remember the background is already white, and because of the need to expose more to bring out the black details, the white background will be overexposed.
So i think u get wat i mean, the camera will only care abt the center 70%.
(c) spot metering - similar to the centre weighted metering, but just that in spot metering, we meter only a small spot eg. a 6mm diameter circle in the picture. This is used for example, when there is a small frog in a bright picture. if u use matrix metering, the camera will evaluate the whole scene and think that the whole picture is too bright, and hence under expose the picture to generate a proper exposure for the whole scene. But in doing so, the small frog may be further underexposed and become dark frog.
in addition, if u use centre weighted metering, remember it assigns abt 70% to the center of the picture, but the frog is only very very small in the picture! hence the end result will also be the camera feels that the scene is too bright and underexpose.
Thus in spot metering, u aim the center crosshair on the frog to meter the frog. This will ensure that the frog is properly exposed and be seen! but of course the background may not be properly exposed
Wednesday, April 14, 2010
Home remedies to Improve Lactation & Breast feeding
My experiences on improving milk prodution during breast feeding.
Breast feed your child for at least minimum six months.
Here are certain home remedies which have helped me improve Lactation & breat feed my baby.
1) Drink 3-4 litres of water daily....very very important
Your body needs lots of fluids during breast- feeding.
2)Have half a litre to one litre of milk daily..
There is One Ayurvedic powder available called SATAVARI- to be taken with milk.....creats wonders to milk secretion.
3)Eat dry grated coconut around 100 gms daily. Even fresh grated coconut is helpful.
4)Eat Carom seeds( Hindi name- Ajwain) around 1-2 teaspoon after every meal.Mildly Roast the carom seeds bafore eating.....this helps to improve the milk secretion and in addition prevents the baby from gastric problems.
5)Eat a bowl of cracked Wheat (Hindi name- Daliya) daily....you can mix milk & sugar to make a desert out of the Daliya or make any spicy recipe as per your choice.
6)Have enough Ghee with your food around 5 tablespoons daily.
7)Fenugreek seeds ( Hindi name- Methi Seeds) should be consumed daily....in the form of sprouted seeds or you can make vegetable or some sweet item by mixing them with rice & jaggery .
8)Juice of Neem Leaves & Neem Stem consumed every morning on empty stomach also helps.
9)Make ladoos by mixing Gum( Marathi name- Dink), wheat flour & dry fruits..eat one every morning
10)For non- vegetarians, you can have one Egg daily & chicken or paya soup.
If you love Fish eat fishes with shells (Mussels)
11)Continue with the prenatal tablets or Calcium/Iron Supplements
*Please do not keep your stomach empty when breast feeding...The Rule is " The More Healthy & Full the Mother eats The More Lactation Improves"
*The Baby has only one source of nutition and that is YOU!!!This is just the extension of your pregnency
Hope this post is Helpful to you.
Breast feed your child for at least minimum six months.
Here are certain home remedies which have helped me improve Lactation & breat feed my baby.
1) Drink 3-4 litres of water daily....very very important
Your body needs lots of fluids during breast- feeding.
2)Have half a litre to one litre of milk daily..
There is One Ayurvedic powder available called SATAVARI- to be taken with milk.....creats wonders to milk secretion.
3)Eat dry grated coconut around 100 gms daily. Even fresh grated coconut is helpful.
4)Eat Carom seeds( Hindi name- Ajwain) around 1-2 teaspoon after every meal.Mildly Roast the carom seeds bafore eating.....this helps to improve the milk secretion and in addition prevents the baby from gastric problems.
5)Eat a bowl of cracked Wheat (Hindi name- Daliya) daily....you can mix milk & sugar to make a desert out of the Daliya or make any spicy recipe as per your choice.
6)Have enough Ghee with your food around 5 tablespoons daily.
7)Fenugreek seeds ( Hindi name- Methi Seeds) should be consumed daily....in the form of sprouted seeds or you can make vegetable or some sweet item by mixing them with rice & jaggery .
8)Juice of Neem Leaves & Neem Stem consumed every morning on empty stomach also helps.
9)Make ladoos by mixing Gum( Marathi name- Dink), wheat flour & dry fruits..eat one every morning
10)For non- vegetarians, you can have one Egg daily & chicken or paya soup.
If you love Fish eat fishes with shells (Mussels)
11)Continue with the prenatal tablets or Calcium/Iron Supplements
*Please do not keep your stomach empty when breast feeding...The Rule is " The More Healthy & Full the Mother eats The More Lactation Improves"
*The Baby has only one source of nutition and that is YOU!!!This is just the extension of your pregnency
Hope this post is Helpful to you.
D50 Lens
The Nikon D50 employs the Nikon DX Format sensor and Nikon F lens mount design. This maintains seamless compatibility with all AF Nikkor lenses and allows photographers to take full advantage of DX Nikkor lenses designed for Nikon's D-series digital SLR cameras and which are optimized to achieve maximum center-to-edge-to-corner image quality.
Compatible Lenses
1) DX Nikkor: All functions supported
2) Type G or D AF Nikkor: All functions supported
3) Micro Nikkor 85 mm F2.8D: All functions supported except autofocus and some exposure modes
4) Other AF Nikkor: All functions supported except 3D Color Matrix Metering II
5) AI-P Nikkor : All functions supported except 3D Color Matrix Metering II and autofocus
6) Non-CPU : Can be used in exposure mode M, but exposure meter does not function; electronic range finder can be used if maximum aperture is f/5.6 or faster
Note: IX Nikkor lenses can not be used
Compatible Lenses
1) DX Nikkor: All functions supported
2) Type G or D AF Nikkor: All functions supported
3) Micro Nikkor 85 mm F2.8D: All functions supported except autofocus and some exposure modes
4) Other AF Nikkor: All functions supported except 3D Color Matrix Metering II
5) AI-P Nikkor : All functions supported except 3D Color Matrix Metering II and autofocus
6) Non-CPU : Can be used in exposure mode M, but exposure meter does not function; electronic range finder can be used if maximum aperture is f/5.6 or faster
Note: IX Nikkor lenses can not be used
Subscribe to:
Posts (Atom)