Hi Everyone:
Anyone know where i can read a book on f-stops and speed. and how they both work together.
Not just f-stop and speed, but ISO as well. They're actually such simple concepts that they hardly merit an entire book. Don't get me wrong, I read TONS of books about photography. However, the triangle of exposure is actually very easy to understand.
Spend a few minutes reading these four sections of a very nice on-line tutorial, and you'll know all there is.
In addition to the most excellent advice above, take your camera, and a lens capable of an f32, out some day when it's sunny outside and set your camera at ISO 200 on Program mode and JPG capture. Take a shot and review the exposure information.
Now change the camera mode to Manual and set the ISO and Aperture and Shutter to match what the program mode showed for exposure. Take another shot to confirm that the 2 exposures match and the scene should look the same. Let's say that the camera chose (for ISO 200 on a sunny day) 1/250th and f22.
Vary one thing at a time.
Start with the Shutter speed. In Manual mode you have direct control of the camera so vary the shutter faster and slower and observe what is happening. As you slow the shutter (let's say 1/125th), the camera lets in more light and you should observe the image brighten. As you speed up the shutter (to 1/500th) the scene should darken as there is less time for the light to expose the imager.
Reset the shutter back to the starting point, 1/250th in this scenario, and this time vary the Aperture. As you open the aperture (smaller numbers) it should allow more light to enter the camera and you should see a brighter image captured. As you close the aperture (larger numbers) you should see the image darken.
Again return the camera settings back to the starting point and this time vary the ISO (sensitivity). As you choose greater sensitivity (higher ISO number) you should see a brighter image and reduced sensitivity should yield a darker image.
Return to the starting ISO and this time vary "2" settings at a time.
Try to maintain a normal exposure while you vary the 2 settings. Lets say you choose to vary shutter speed and aperture. To maintain a proper exposure you change one setting and then "counter" with the other setting. A longer exposure requires a smaller aperture to maintain proper exposure.
Once you grasp these simple concepts you will have the ability to "control" your exposure to match the scene and image goals of your photography.
I appreciate the info here, since I am venturing off of auto and onto actually driving the camera.
Even after I grasped the concept of ISO, Fstops, Shutter speed I still struggle when I get out to shoot on what to do first? Where do I start? I panic and jump back to auto ( not nearly as much now! ) ...
Being dyslexic does not help ! SO thank you ! This helps a great deal.
I appreciate the info here, since I am venturing off of auto and onto actually driving the camera.
Even after I grasped the concept of ISO, Fstops, Shutter speed I still struggle when I get out to shoot on what to do first? Where do I start? I panic and jump back to auto ( not nearly as much now! ) ...
Being dyslexic does not help !
Thanks for all the info on the site.
Depending on the exact nature and degree of your dyslexia it may seem very confusing.
I suggest simplifying the camera control system as much as the camer allows to start. For instance if your camera allows settings of full stops, choose that instead of the fractional stops. Then use Exposure Compensation to fine tune the exposure up or down.
Practicing a lot in a non-stress environment can also help. If you are just practicing and the results don't matter and if you have plenty of time to experiment, that can make the learning easier.
A patient coach can also help.
A printed exposure guide can also help with manual exposure. Here is a very simple start which may, or may not, work with your camera. Feel free to create your own chart based on the qualities of your own camera system.
Note that this chart is based upon both a Kodak exposure guide and the "sunny 16" rule, and then adjusted by me for digital purposes where protecting the highlights is pretty important. "Your" camera may require some deviation from these settings for optimal results.
Starting with these settings and then using your in-camera histogram and "blinkies" (highlight indicators) is also helpful, but ultimately even those need to be tempered by your understanding of what they mean. You may find that the histogram is conservative or aggressive and have to compensate for that tendency.
Depending on the exact nature and degree of your dyslexia it may seem very confusing.
I suggest simplifying the camera control system as much as the camer allows to start. For instance if your camera allows settings of full stops, choose that instead of the fractional stops. Then use Exposure Compensation to fine tune the exposure up or down.
Practicing a lot in a non-stress environment can also help. If you are just practicing and the results don't matter and if you have plenty of time to experiment, that can make the learning easier.
A patient coach can also help.
A printed exposure guide can also help with manual exposure. Here is a very simple start which may, or may not, work with your camera. Feel free to create your own chart based on the qualities of your own camera system.
Note that this chart is based upon both a Kodak exposure guide and the "sunny 16" rule, and then adjusted by me for digital purposes where protecting the highlights is pretty important. "Your" camera may require some deviation from these settings for optimal results.
Starting with these settings and then using your in-camera histogram and "blinkies" (highlight indicators) is also helpful, but ultimately even those need to be tempered by your understanding of what they mean. You may find that the histogram is conservative or aggressive and have to compensate for that tendency.
I appreciate the info here, since I am venturing off of auto and onto actually driving the camera.
Even after I grasped the concept of ISO, Fstops, Shutter speed I still struggle when I get out to shoot on what to do first? Where do I start? I panic and jump back to auto ( not nearly as much now! ) ...
Being dyslexic does not help ! SO thank you ! This helps a great deal.
Thanks for all the info on the site.
You don't mention where your dyslexia is, but books can be a lot to work thru for anyone, I get info overload easy~
Taking from Ziggy's post about setting yourself and camera up to experiment is a great idea.
Camera up on tripod.
When you are in Manual
You have a viewfinder that has a meter at the bottom> ......|......
ISO 200, f/8, shutter 1000th. Where is the Meter? ...|........ or .........|...
Adjust the Shutter speed so the meter thru the viewfinder is like so.......|........ or centered.
Now take a photo. looking at the LCD it should look decently exposed.
Now, adjust ISO. Adjust ISO up to 400.
look at the meter it should move from ......|...... to ...|......... This indication can be reversed in a menu setting so I may have it backward for your camera.
The meter is telling you you have to adjust the shutter speed to once again properly expose.
So up the Shutter speed to get the meter in the middle again> .....|.....
and take another photo.
Continue in this vein, asking yourself questions along the way. ie: " what will happen if I up the ISO to 1200 now?", etc.
DO that and then you'll have your experiment in full swing and order.
Early on I would set my camera up right here in front of my keyboard and read right off of the Internet and adjust and take photos of my monitor screen...I couldn't remember this stuff far enough to walk outside
You don't mention where your dyslexia is, but books can be a lot to work thru for anyone, I get info overload easy~
Taking from Ziggy's post about setting yourself and camera up to experiment is a great idea.
Camera up on tripod.
When you are in Manual
You have a viewfinder that has a meter at the bottom> ......|......
ISO 200, f/8, shutter 1000th. Where is the Meter? ...|........ or .........|...
Adjust the Shutter speed so the meter thru the viewfinder is like so.......|........ or centered.
Now take a photo. looking at the LCD it should look decently exposed.
Now, adjust ISO. Adjust ISO up to 400.
look at the meter it should move from ......|...... to ...|......... This indication can be reversed in a menu setting so I may have it backward for your camera.
The meter is telling you you have to adjust the shutter speed to once again properly expose.
So up the Shutter speed to get the meter in the middle again> .....|.....
and take another photo.
Continue in this vein, asking yourself questions along the way. ie: " what will happen if I up the ISO to 1200 now?", etc.
DO that and then you'll have your experiment in full swing and order.
Early on I would set my camera up right here in front of my keyboard and read right off of the Internet and adjust and take photos of my monitor screen...I couldn't remember this stuff far enough to walk outside
Good Luck~
My challenge is with aperture.. the larger the number the smaller the opening?.. ( WHO invented that? haha), I go into overload right there.. so what I've been doing ( until I can get it all in ) is setting cameral on Tv since I do get Shutter speed and trying that way. The camera is setting the aperture but I want to control it all.. I want to get this.
Your explanation does make sense and its a stay in day so will be trying this out, thank you!
I moved this to the Technique forum and I surely hope that Pathfinder jumps in here with his take on the discussion. Understanding exposure is a pivotal concept in photography and Jim has dedicated a tremendous amount of time and resources to the topic.
My challenge is with aperture.. the larger the number the smaller the opening?.. ( WHO invented that? haha), I go into overload right there.. so what I've been doing ( until I can get it all in ) is setting cameral on Tv since I do get Shutter speed and trying that way. The camera is setting the aperture but I want to control it all.. I want to get this.
Your explanation does make sense and its a stay in day so will be trying this out, thank you!
This page is a pretty good explaination of the relationship between f-stop, aperture size, and focal length.
Roughly speaking, f/2.8 really means....
aperture diamater (the actual size of the hole) = focal length / 2.8
So, let's take my favorite lens (today anyway ), the EF 70-200 f/2.8L IS
At 200mm and f/2.8, the size of the hole (aperture) has to be 71.4mm in diameter.
Slightly off-topic: This goes a long way towards explaining why the filter size for this lens is 77mm. And why you will be very hard pressed to find a 200mm f/1.2 lens - the aperture would need to be (approx) 167mm (or approx 6.6 inches) in diameter.
My challenge is with aperture.. the larger the number the smaller the opening?.. ( WHO invented that? haha), I go into overload right there.. so what I've been doing ( until I can get it all in ) is setting cameral on Tv since I do get Shutter speed and trying that way. The camera is setting the aperture but I want to control it all.. I want to get this.
Your explanation does make sense and its a stay in day so will be trying this out, thank you!
You can do the same thing as I described above using any one of those settings. I used ISO to drive Shutter speed in my example.
But you could just as easily use f/# to drive shutter speed. Do my set up as described above but instead of adjusting your shutter, adjust your f/# ( you may still have to adjust your shutter too a bit)
If it is a stay in day, you'll be closer to the info here.
You can do the same thing as I described above using any one of those settings. I used ISO to drive Shutter speed in my example.
But you could just as easily use f/# to drive shutter speed. Do my set up as described above but instead of adjusting your shutter, adjust your f/# ( you may still have to adjust your shutter too a bit)
If it is a stay in day, you'll be closer to the info here.
Cheers,
The shutter speed is the one thing I can process mentally in a pinch.. so I stay with that.
This page is a pretty good explaination of the relationship between f-stop, aperture size, and focal length.
Roughly speaking, f/2.8 really means....
aperture diamater (the actual size of the hole) = focal length / 2.8
So, let's take my favorite lens (today anyway ), the EF 70-200 f/2.8L IS
At 200mm and f/2.8, the size of the hole (aperture) has to be 71.4mm in diameter.
Slightly off-topic: This goes a long way towards explaining why the filter size for this lens is 77mm. And why you will be very hard pressed to find a 200mm f/1.2 lens - the aperture would need to be (approx) 167mm (or approx 6.6 inches) in diameter.
Fstops is a ratio of the focal length divided by the effective aperture - this ratio is used so that an fstop of a 28mm lens, or a 300mm lens, or a 180mm lens all admit the same amount of light for a given shutter speed. Otherwise we would have to reset an exposure differently for each lens we use.
Large f numbers f28 say, means that the diameter of the front of the lens in millimeters, will divide into the focal length 28 times, thus the opening must be very small. An f1.0 50mm lens, must be 50 mm in diameter as well as focal length. Or an f1.0 500mm lens, would be 500mm - roughly 1/2 meter in diameter. Needless to say, there are no real 500mm f1.0 lenses for sale. Sigma does make an f2.8 200 - 500mm zoom - a very fast telephoto for a mere $29,000
Canon did manufacture a f0.95 50mm lens for a while. Now the fastest 50mm they make, is f1.2
As lenses get larger in diameter, relative to focal length, they get "faster" ie: admit more light per second. But they also get much heavier, and optically much more complex and much, much, much more expensive. Price a 300mm f2.8 versus a 300mm f4 - just one fstop difference - and you will see what I mean.
White balance does not affect exposure at all - it is the overall color, tone, hue of your image. You cannot set white balance with a poorly exposed image.
You can set your camera to AWB, Shade, Sunlight, Flash, Fluorescent etc - These settings may or may not be what you really want however. Ultimately the "Correct" white balance is the one, you, the artist chooses. When you shot film, the color balance was set by the technicians who manufactured the film. Daylight, Tungsten, Infra-red, etc.
If you are shooting color patches for a catalog, color balance is critical, and best done with a Custom white balancing tool like on of these - http://www.dgrin.com/showthread.php?t=90438
Custom white balancing can be done/ should be done in RAW processing with RAW files. Jpgs need to have the correct white balance chosen/set at the time of shooting. The baked in camera white balance of 8bit jpgs is hard to change very much without damaging the jpg file. A custom in camera white balance is better for shooting jpgs that must be color balance correct.
I've only just skimmed this thread as I'm on my way out of the door but have saved it for later! Just wanted to say that I am in a very similar position (just starting to 'drive' the camera). I had the above book recommended to me and it has been fantastic in helping me to understand what's what! There's no substitute for going out with you camera and trying things out practically of course but the author has a really informal style and a good way of explaining things. I'm sure it's not everyone's cup of tea but it's worked for me:)
More practice needed but learning all the time!:rofl
Nikon D50, 18mm-55mm, 55mm-200mm, 50mm f/1.8, SB800, LowePro Slingshot 200AW and other bits!
Thanks to everyone for all the time they took to reply ..I really appreciate the effort, on this topic..I thank you from the bottom of my Heart and Bow down graciously.."salaam" Time for some good reading..and understanding of lighting, speed and aperture and how they both work.. together.
Eddy
E.J.W
Great understanding is broad and unhurried, Little understanding is cramped and busy" ..... Chuang Tsu
Thanks to everyone for all the time they took to reply ..I really appreciate the effort, on this topic..I thank you from the bottom of my Heart and Bow down graciously.."salaam" Time for some good reading..and understanding of lighting, speed and aperture and how they both work.. together.
Eddy
Why are they like that?
Suppose we have a 50mm focal length lens. If we have a big size hole - a big aperture, it might measure 25mm. So 50 divided by 25 gives us 2: the f/number is 2, which we write as f/2.
If the aperture is smaller, say, 3mm in diameter, 50 divided by 3 gives us about 16: the f/number reads f/16. As the hole is smaller, less light gets through. So f/16 is said to be a small aperture or small f/number.
That’s why you could get confused if you read about an aperture of 16 being smaller than 2: that does not make sense and is, in fact, wrong. A photographic aperture is written as ‘f/number’: it means the focal length divided by the aperture diameter. So f/16 is indeed smaller than f/2. (Microscopists talk about numerical aperture, but that’s a different thing.)
does this mean he is talking about the diameter fo the end of the lens where the filter goes on ...yes/no
E.J.W
Great understanding is broad and unhurried, Little understanding is cramped and busy" ..... Chuang Tsu
F-stop
(big hole lets light in fast)..............................................................(small hole lets same amount of light in slow at given exposure)
2.8 4 5.6 8 11 past here it gets pretty slow and may need a tripod 16 20 22.
ISO
(sensor is less sensitive to light).......................................(sensor is more sensitive to light)
100 200 400 past here some cameras will start to get noise 800 1600 3200
Shutter speed
(lets lots of light in fast)........................................................................(lets same amount of light in slow for a given exposure)
4000 2000 1000 500 125 around here is where you will start getting motion blur generally 80 40 etc..
Will vary with lighting conditions but chart above is a rough outline of the relationship.....as simple as I could make it.
The relationship of these three is what determing exposure and shutter speed.
Suppose we have a 50mm focal length lens. If we have a big size hole - a big aperture, it might measure 25mm. So 50 divided by 25 gives us 2: the f/number is 2, which we write as f/2.
If the aperture is smaller, say, 3mm in diameter, 50 divided by 3 gives us about 16: the f/number reads f/16. As the hole is smaller, less light gets through. So f/16 is said to be a small aperture or small f/number.
That’s why you could get confused if you read about an aperture of 16 being smaller than 2: that does not make sense and is, in fact, wrong. A photographic aperture is written as ‘f/number’: it means the focal length divided by the aperture diameter. So f/16 is indeed smaller than f/2. (Microscopists talk about numerical aperture, but that’s a different thing.)
does this mean he is talking about the diameter fo the end of the lens where the filter goes on ...yes/no
The aperture is generally the diameter of the front element of the lens.
Ha ... Thanks guys...now it's all making sense to me...the answer to the sum i was getting was way outta wack to say the least.. nice perspective on it from you both thank you very much
Eddy
E.J.W
Great understanding is broad and unhurried, Little understanding is cramped and busy" ..... Chuang Tsu
Comments
On that might be just what you are looking for is Understanding Exposure: How to Shoot Great Photographs with a Film or Digital Camera (Updated Edition)
My Photos
Thoughts on photographing a wedding, How to post a picture, AF Microadjustments?, Light Scoop
Equipment List - Check my profile
Spend a few minutes reading these four sections of a very nice on-line tutorial, and you'll know all there is.
Stops
Shutter and Aperture
Film Speed (ISO)
-joel
Link to my Smugmug site
Now change the camera mode to Manual and set the ISO and Aperture and Shutter to match what the program mode showed for exposure. Take another shot to confirm that the 2 exposures match and the scene should look the same. Let's say that the camera chose (for ISO 200 on a sunny day) 1/250th and f22.
Vary one thing at a time.
Start with the Shutter speed. In Manual mode you have direct control of the camera so vary the shutter faster and slower and observe what is happening. As you slow the shutter (let's say 1/125th), the camera lets in more light and you should observe the image brighten. As you speed up the shutter (to 1/500th) the scene should darken as there is less time for the light to expose the imager.
Reset the shutter back to the starting point, 1/250th in this scenario, and this time vary the Aperture. As you open the aperture (smaller numbers) it should allow more light to enter the camera and you should see a brighter image captured. As you close the aperture (larger numbers) you should see the image darken.
Again return the camera settings back to the starting point and this time vary the ISO (sensitivity). As you choose greater sensitivity (higher ISO number) you should see a brighter image and reduced sensitivity should yield a darker image.
Return to the starting ISO and this time vary "2" settings at a time.
Try to maintain a normal exposure while you vary the 2 settings. Lets say you choose to vary shutter speed and aperture. To maintain a proper exposure you change one setting and then "counter" with the other setting. A longer exposure requires a smaller aperture to maintain proper exposure.
Once you grasp these simple concepts you will have the ability to "control" your exposure to match the scene and image goals of your photography.
Moderator of the Cameras and Accessories forums
Even after I grasped the concept of ISO, Fstops, Shutter speed I still struggle when I get out to shoot on what to do first? Where do I start? I panic and jump back to auto ( not nearly as much now! ) ...
Being dyslexic does not help ! SO thank you ! This helps a great deal.
Thanks for all the info on the site.
Great understanding is broad and unhurried, Little understanding is cramped and busy" ..... Chuang Tsu
Depending on the exact nature and degree of your dyslexia it may seem very confusing.
I suggest simplifying the camera control system as much as the camer allows to start. For instance if your camera allows settings of full stops, choose that instead of the fractional stops. Then use Exposure Compensation to fine tune the exposure up or down.
Practicing a lot in a non-stress environment can also help. If you are just practicing and the results don't matter and if you have plenty of time to experiment, that can make the learning easier.
A patient coach can also help.
A printed exposure guide can also help with manual exposure. Here is a very simple start which may, or may not, work with your camera. Feel free to create your own chart based on the qualities of your own camera system.
Note that this chart is based upon both a Kodak exposure guide and the "sunny 16" rule, and then adjusted by me for digital purposes where protecting the highlights is pretty important. "Your" camera may require some deviation from these settings for optimal results.
Starting with these settings and then using your in-camera histogram and "blinkies" (highlight indicators) is also helpful, but ultimately even those need to be tempered by your understanding of what they mean. You may find that the histogram is conservative or aggressive and have to compensate for that tendency.
Moderator of the Cameras and Accessories forums
Thank you...thank you!
Taking from Ziggy's post about setting yourself and camera up to experiment is a great idea.
Camera up on tripod.
When you are in Manual
You have a viewfinder that has a meter at the bottom> ......|......
ISO 200, f/8, shutter 1000th. Where is the Meter? ...|........ or .........|...
Adjust the Shutter speed so the meter thru the viewfinder is like so.......|........ or centered.
Now take a photo. looking at the LCD it should look decently exposed.
Now, adjust ISO. Adjust ISO up to 400.
look at the meter it should move from ......|...... to ...|......... This indication can be reversed in a menu setting so I may have it backward for your camera.
The meter is telling you you have to adjust the shutter speed to once again properly expose.
So up the Shutter speed to get the meter in the middle again> .....|.....
and take another photo.
Continue in this vein, asking yourself questions along the way. ie: " what will happen if I up the ISO to 1200 now?", etc.
DO that and then you'll have your experiment in full swing and order.
Early on I would set my camera up right here in front of my keyboard and read right off of the Internet and adjust and take photos of my monitor screen...I couldn't remember this stuff far enough to walk outside
Good Luck~
My challenge is with aperture.. the larger the number the smaller the opening?.. ( WHO invented that? haha), I go into overload right there.. so what I've been doing ( until I can get it all in ) is setting cameral on Tv since I do get Shutter speed and trying that way. The camera is setting the aperture but I want to control it all.. I want to get this.
Your explanation does make sense and its a stay in day so will be trying this out, thank you!
Moderator of the Cameras and Accessories forums
Roughly speaking, f/2.8 really means....
aperture diamater (the actual size of the hole) = focal length / 2.8
So, let's take my favorite lens (today anyway
At 200mm and f/2.8, the size of the hole (aperture) has to be 71.4mm in diameter.
Slightly off-topic: This goes a long way towards explaining why the filter size for this lens is 77mm. And why you will be very hard pressed to find a 200mm f/1.2 lens - the aperture would need to be (approx) 167mm (or approx 6.6 inches) in diameter.
My Photos
Thoughts on photographing a wedding, How to post a picture, AF Microadjustments?, Light Scoop
Equipment List - Check my profile
You can do the same thing as I described above using any one of those settings. I used ISO to drive Shutter speed in my example.
But you could just as easily use f/# to drive shutter speed. Do my set up as described above but instead of adjusting your shutter, adjust your f/# ( you may still have to adjust your shutter too a bit)
If it is a stay in day, you'll be closer to the info here.
Cheers,
The shutter speed is the one thing I can process mentally in a pinch.. so I stay with that.
Time to move out of my comfort zone...
That is a great page.. and doesn't make me feel so inadequate trying to understand.
My Photos
Thoughts on photographing a wedding, How to post a picture, AF Microadjustments?, Light Scoop
Equipment List - Check my profile
You should try it when they are on backwards...
I really wonder about myself, dyslexic and color blind attempting photography
Maybe that's why I am determined!
Wiki has a great discussion of fstops
Fstops is a ratio of the focal length divided by the effective aperture - this ratio is used so that an fstop of a 28mm lens, or a 300mm lens, or a 180mm lens all admit the same amount of light for a given shutter speed. Otherwise we would have to reset an exposure differently for each lens we use.
Large f numbers f28 say, means that the diameter of the front of the lens in millimeters, will divide into the focal length 28 times, thus the opening must be very small. An f1.0 50mm lens, must be 50 mm in diameter as well as focal length. Or an f1.0 500mm lens, would be 500mm - roughly 1/2 meter in diameter. Needless to say, there are no real 500mm f1.0 lenses for sale. Sigma does make an f2.8 200 - 500mm zoom - a very fast telephoto for a mere $29,000
Canon did manufacture a f0.95 50mm lens for a while. Now the fastest 50mm they make, is f1.2
As lenses get larger in diameter, relative to focal length, they get "faster" ie: admit more light per second. But they also get much heavier, and optically much more complex and much, much, much more expensive. Price a 300mm f2.8 versus a 300mm f4 - just one fstop difference - and you will see what I mean.
Moderator of the Technique Forum and Finishing School on Dgrin
That is a great piece.. I am trying to comprehend the Sunny 16 rule.. would be nice to have a rule of thumb to start with.
Love the moon shot, I am always struggling with the moon and I love shooting it.
Can you tell me where WB comes into play with all of this?
You can set your camera to AWB, Shade, Sunlight, Flash, Fluorescent etc - These settings may or may not be what you really want however. Ultimately the "Correct" white balance is the one, you, the artist chooses. When you shot film, the color balance was set by the technicians who manufactured the film. Daylight, Tungsten, Infra-red, etc.
If you are shooting color patches for a catalog, color balance is critical, and best done with a Custom white balancing tool like on of these - http://www.dgrin.com/showthread.php?t=90438
Custom white balancing can be done/ should be done in RAW processing with RAW files. Jpgs need to have the correct white balance chosen/set at the time of shooting. The baked in camera white balance of 8bit jpgs is hard to change very much without damaging the jpg file. A custom in camera white balance is better for shooting jpgs that must be color balance correct.
Moderator of the Technique Forum and Finishing School on Dgrin
I've only just skimmed this thread as I'm on my way out of the door but have saved it for later! Just wanted to say that I am in a very similar position (just starting to 'drive' the camera). I had the above book recommended to me and it has been fantastic in helping me to understand what's what! There's no substitute for going out with you camera and trying things out practically of course but the author has a really informal style and a good way of explaining things. I'm sure it's not everyone's cup of tea but it's worked for me:)
Nikon D50, 18mm-55mm, 55mm-200mm, 50mm f/1.8, SB800, LowePro Slingshot 200AW and other bits!
OMG... I did it. This will help me a great deal !
*takes a bow*
Eddy
Great understanding is broad and unhurried, Little understanding is cramped and busy" ..... Chuang Tsu
Why are they like that?
Suppose we have a 50mm focal length lens. If we have a big size hole - a big aperture, it might measure 25mm. So 50 divided by 25 gives us 2: the f/number is 2, which we write as f/2.
If the aperture is smaller, say, 3mm in diameter, 50 divided by 3 gives us about 16: the f/number reads f/16. As the hole is smaller, less light gets through. So f/16 is said to be a small aperture or small f/number.
That’s why you could get confused if you read about an aperture of 16 being smaller than 2: that does not make sense and is, in fact, wrong. A photographic aperture is written as ‘f/number’: it means the focal length divided by the aperture diameter. So f/16 is indeed smaller than f/2. (Microscopists talk about numerical aperture, but that’s a different thing.)
does this mean he is talking about the diameter fo the end of the lens where the filter goes on ...yes/no
Great understanding is broad and unhurried, Little understanding is cramped and busy" ..... Chuang Tsu
F-stop
(big hole lets light in fast)..............................................................(small hole lets same amount of light in slow at given exposure)
2.8 4 5.6 8 11 past here it gets pretty slow and may need a tripod 16 20 22.
ISO
(sensor is less sensitive to light).......................................(sensor is more sensitive to light)
100 200 400 past here some cameras will start to get noise 800 1600 3200
Shutter speed
(lets lots of light in fast)........................................................................(lets same amount of light in slow for a given exposure)
4000 2000 1000 500 125 around here is where you will start getting motion blur generally 80 40 etc..
Will vary with lighting conditions but chart above is a rough outline of the relationship.....as simple as I could make it.
The relationship of these three is what determing exposure and shutter speed.
http://www.flickr.com/photos/21695902@N06/
http://500px.com/Shockey
alloutdoor.smugmug.com
http://aoboudoirboise.smugmug.com/
The aperture is generally the diameter of the front element of the lens.
I once measured the diameter of some of my lenses and compared them to focal lengths here - http://digitalgrin.com/showthread.php?t=45735
Moderator of the Technique Forum and Finishing School on Dgrin
Eddy
Great understanding is broad and unhurried, Little understanding is cramped and busy" ..... Chuang Tsu