funny you should say that adrian. i remember you saying about the cannon 50 mm f?1.8 prime lens in my other thread. i just bought 1 today . got it for £69. and i see what you were on about regarding it being a good lens to learn photograpghy with. i found that with the kit lens it is very easy to get good results once you have a basic understanding of shutter speed , aperture , iso etc . but after havng a brief play with this lens i can see it will produce very good results BUT it requires a lot more input from the user and given that i hope to become a good photographer that can only be a good thing .
raptorex . its clearly obvious you know your subject in great detail , but for me im just feeling my way in slowly at the moment . once i have a good grasp of the basics i will delve into the slightly more complex side of things , but for now im happy just experementing with shutter speeds , exposures etc.
I sorry if i come across "stuffy" on this. its just so many people now thing the DIGITAL has changed the basics of photography, some how. and the truth is, its the same today as it was 100 years ago. people get lost in the Tech, when the principals are quite simple.
I will always help, if i can, this is a fantastic hobby. unfortunately the Electronics seem more important than the fundamentals.
here are some basics. see if you can follow my reasoning.
1, shutter speed. this is the mechanism used to dictate the LENGTH of time, any, light is allowed to reach the sensor. it, like all exposure components, is broken up into STOPS. one STOP is when the amount of light is, either doubled or halved. so 60th of a second is one stop less than 125th of a second. logically, 30th of a second is one stop more than 60th of a second.
2, aperture. this dictates the amount of light that reaches the sensor. again its brocken up into STOPS. so F3.5 will be one stop more (faster) than f8. and one STOP (slower) than 1.8.
the two above have other effects on your pictures too. but one step at a time!
people often miss the fact that there is only one amount of light, at a given ASA/ISO, that will allow a correctly exposed picture. so the above functions have to work together to ensure that enough light gets to the sensor, for the correct amount of time.
therefore if your camera says the picture is correctly exposed at 125th of a second at F5.6. the picture would also be correctly exposed at, 250th of a second at F2.8.
now a bit of, possibly, usless information. we all know what 125th of a second means (its a fraction of a second). but few know what the number used to denote apertures means.
for the system to work, all lenses must, at any given setting, transmit the same amount of light. but as a lens increases in focal length, the opening needed, to do this, gets much bigger. so a wide angle lens of 28mm will have an aperture size of 10mm @ f2.8 and a 500mm would have an aperture size of 178 and a bit mm. this varience in size could cause problems, so as with most things there is a mathematical formula to explain it. and that is what the aperture number is. turns out if you multiply the aperture size by the focal length, on any lens. the resultant number transmits the same amount of light at that setting. so dividing the focal length by the aperture set, gives you the exact size of aperture, on any lens. and the amount of light transited will be identical in every case.
/www.fishforums.net/index.php?/topic/349622-been-playing-with-the-new-camera/ i think you can notice the difference
