Canon Lens.

[Snatcher]

A really interesting thread but way over my head at the mo I really bought my Canon Powershot to take photos of my catch at the waterside and holiday/landscape snaps. I do find myself being drawn more into photography now though.

 

I can see me possibly getting a telescopic lens in the future but I think that will be as far as it goes. Any idea on prices and models to fit an A700?

[Chippy]

@Chippy. What is a full frame sensor? And how much do they cost? And are they worth it?

 

They are full frame, as in, the same size (36mm x 24mm - from memory) as a 35mm film frame. In effect there is no multiplyer factor for lenses, so a 24mm lens stays as being a 24mm lens, it doesnt become effectively a 36mm (24mm x 1.5) or whatever.

 

Full frame a great for wide angle because there's less distortion - for instance to get a the same 21mm field of view (on fullframe) on a "cropped" sensor, which has a x1.5 multiplyer, you'd have to use a 14mm lens - much more distortion the wider you go.

 

At the other end of the scale, a user with a cropped sensor camera can use a smaller and lighter 400mm lens and have an effective 600mm. A full frame camera would need to use a much larger and heavier 600mm lens to get the same effective focal length.

 

Full frame sensors are (currently) VERY expensive. The Canon 5D is the cheapest one that comes to mind (12 million pixels) or the Canon 1Ds (16.5 million).

 

Because of the angle of view of full frame cameras, they also have a larger image circle and therefore lenses designed for small sensor cameras generally wont work. This also means that they tend to use much more of the lenses surface and generally speaking require top quality glass as the larger sensor tends to show up quality failings on cheaper lenses.

[Hellbelly]

OK, thanks Chippy. I think I wont be getting a full frame sensor then. The budget is being stretched as it is just to get the 400D let alone the lens'. We're looking at getting one around mid January. Will be going for the two lens packaged camera to start with, then will be aiming at getting one of those better lans' you mentioned.

 

HB.

[Yogi]

Been looking at Warehouse Express on site. I would like a new lens (or two) but trying to decide which one is a mine field. So many to choose from and at a price

 

I like the look of the 28-135 with a aperture of 3.5-5.6 and with a IS system at £309.

 

Am also torn between the 100-400 with a aperture of 4.5-5.6 L IS USM at £1042. Or the 70-200 with a aperture of 2.8 L IS USM at £1249. Plus the X2 converter at £229. For me the 100-400 lens has a too slow aperture but I like the long focal length. The X2 converter on the 70-200 will add an extra 2 stops but the IS will reduce that.

 

It's a catch 22 eh.

 

Yogi

[Chippy]

Am also torn between the 100-400 with a aperture of 4.5-5.6 L IS USM at £1042. Or the 70-200 with a aperture of 2.8 L IS USM at £1249. Plus the X2 converter at £229. For me the 100-400 lens has a too slow aperture but I like the long focal length. The X2 converter on the 70-200 will add an extra 2 stops but the IS will reduce that.

 

It's a catch 22 eh.

 

Yogi

 

 

I had the same decision to make too

 

Ended up going for the 70-200 2.8IS. I figured the two extra stops of speed would be more use than the extra focal length for the time being. Some have complained that the push/pull design of the 100-400 also increases sensor dust.

[phil dean]

most of my photos seem to be ebing taken with the sigma 70 - 300 i bought from jessops for a little over £100 online.

 

it really has been very good value, both of the shots in the "anything goes" comp were taken with it.

 

other than that I have the standard kit lense (18 -55mm) and a sigma 35 -80 which I hardly use.

[Hellbelly]

OK, so I've been shopping around. Missed out on a 17-40 yesterday by $8. Not happy. I was at work so had a program bid for me but my top limit was less than the other guys. Anyway, back to my point. If a 17-40 is$930 (AU) and a 17-85 is cheaper at $690, then why is it that a 17-55 is more expencive than both of them. I thought it would follow that the "85" number is cheapest, so I assumed that going lower in that number would slowly increase price. So why is the 55, with higher number than the "40", more expencive?

 

And that just the start. I wanna know what the f stops are, how you get a good "DOF" and much more. I've been awake half the night with camera numbers spinning around my head (and I'm back at work).

 

Cheers.........HB

 

PS is a Sigma 70-300 any good?

Edited December 27, 2006 by Hellbelly

[Chippy]

And that just the start. I wanna know what the f stops are, how you get a good "DOF" and much more. I've been awake half the night with camera numbers spinning around my head (and I'm back at work).

 

Cheers.........HB

 

PS is a Sigma 70-300 any good?

 

 

Fairly simple. 1 x f stop lets through/reduces twice as much light as the next F stop. So F4 lets in twice as much light as F5.6.

 

Because this doesnt effect smaller focal length lenses as much as telephotos - where camera shake and higher shutter are required, price differences tend to be smaller. However, try comparing the price of a 400mm F4 to a 400mm F2.8 - it's huge!!

 

Generally speaking on a "wide" lens you they tend to be used around F8-F16 for greater depth of field, whereas teles tend to be used around F2.8-F4 to get higher shutter speeds.

 

Also remember that a 20mm lens at F4 will give you much more depth of field that a 200mm lens at F4 !!

 

You'll also find that a lot of "pro" lenses which tend to be F2.8 or thereabouts also use superior glass elements like aspherical and flourite elements, which is why they are often much more expensive.

 

My 17-40mm F4 is my favourite landscape lens......VERY sharp and nice and light too.

[phil dean]

most people who've had a play with the sigma 70 - 300 were very impressed I think it's f5, not got at work with me.

[Yogi]

Well, today I got myself a Canon 28-135 IS USM for £275 brand new.

 

Not even tried it on my camera yet.

 

Yogi.