Lenses questions

[Salah Yousef]

Hey everyone. This is my third thread in this forum. I have a few questions about lenses and hope I get answers.

1- mm stands for millimeter right ?

2- How do you know which lens is better in zooming and auto focus ?

3- Why is http://www.amazon.com/Canon-50mm-1-8-Camera-Lens/dp/B00007E7JU/ref=sr_1_1?ie=UTF8&qid=1376730608&sr=8-1&keywords=Canon+EF+50mm+F%2F1.8+II cheaper than http://www.amazon.com/Canon-40mm-2-8-STM-Lens/dp/B00894YP00/ref=sr_1_1?ie=UTF8&qid=1376730637&sr=8-1&keywords=canon+40mm that one is 50mm and the other is 40mm

4- What does EF stand for ? example: Canon EF 100mm

5- What does FD and EF mount stand for ?

Thank you.

 

[Vossie]

1. Yes, this is the focal length of the lens. 50mm is considered "normal" focal length as the angle of view is very "natural" to our eyes. 100mm has half the angle of view as 50mm and 25mm has double the amgle of view of 50mm. Anything wider than 50mm is referred to as wide angle, anything narrower is referred to as tele. As comparison an 8x binocular has approximately the angle of view as a 8x50=400mm lens.
2. By reading reviews. Looking at the specs of the AF motor can also give you a hint. http://www.the-digital-picture.com is a great resource for (Canon) info. Google is good as well
3. Price is dependent on the make costs of a lens and not on the focal lenght. The material use and complexity of the lens design are key factors determining lens prices. The 50mm 1.8 is made from very cheap materials. Canon has 2 more 50mm lenses that are brighter (more glass needed) and more complex and use better materials but are much more expensive (the 50 1.2 is over 1000 usd).
4. Electro-Focus. Have a look at this wiki for background: http://en.wikipedia.org/wiki/Canon_EF_lens_mount All modern Canon SLRs use this mount. (EF-S found on crop bodies is a variant of EF and compatible with EF lenses).
5. FD is the old manual focus Canon mount. You can fit old FD lenses on EF mount bodies using special adapters; Ed Mika, whomis also on this forum makes these adaptors.

Cheers.

 

[Salah Yousef]

1. Yes, this is the focal length of the lens. 50mm is considered "normal" focal length as the angle of view is very "natural" to our eyes. 100mm has half the angle of view as 50mm and 25mm has double the amgle of view of 50mm. Anything wider than 50mm is referred to as wide angle, anything narrower is referred to as tele. As comparison an 8x binocular has approximately the angle of view as a 8x50=400mm lens.
2. By reading reviews. Looking at the specs of the AF motor can also give you a hint. http://www.the-digital-picture.com is a great resource for (Canon) info. Google is good as well
3. Price is dependent on the make costs of a lens and not on the focal lenght. The material use and complexity of the lens design are key factors determining lens prices. The 50mm 1.8 is made from very cheap materials. Canon has 2 more 50mm lenses that are brighter (more glass needed) and more complex and use better materials but are much more expensive (the 50 1.2 is over 1000 usd).
4. Electro-Focus. Have a look at this wiki for background: http://en.wikipedia.org/wiki/Canon_EF_lens_mount All modern Canon SLRs use this mount. (EF-S found on crop bodies is a variant of EF and compatible with EF lenses).
5. FD is the old manual focus Canon mount. You can fit old FD lenses on EF mount bodies using special adapters; Ed Mika, whomis also on this forum makes these adaptors.

Cheers.

Arigato Vossie kun! ^_^

Thank you.