Wide Aperture Zooms

[Dolby]

Is it difficult or expensive to make wide aperture zooms? :/

It seems if you want anything less than 2.8, you need to go prime ... or have a I missed a lens? I'd love a 1.8 zoom (even small like 18-55)

 

[BigAl-sa]

Yes, physics is difficult

 

[Dolby]

I'd have thought at least Canon would be able to bypass physics?

Nikon I'd understand though ...

 

[koffiejunkie]

It's not that difficult to make a zoom with an aperture larger than 2.8. What's difficult is making one that's any good. I've use an old 28-70 or something around there 2.8 zoom, Vivitar perhaps. It was far more compact than modern 24-70mm f/2.8 lenses, but it wasn't very good either. Heavy barrel distortion on the wide end, heavy colour fringing, very soft below about, uhm f/8, poor contrast below, uhm, f/8

 

[Dolby]

Bringing this thread back to life ...

Looking at the Canon S100 which is considered to be a great camera - it has a 24mm-120mm (equivalent) F2.0-5.9. If they can do that in the compact camera, surely it wouldn't be *that* expensive or difficult to manufacture a 18-55 (F2.0 - 4.0)?

This little Olympus XZ-1 is 28mm-112mm F1.8-2.5 is even better http://www.olympusamerica.com/cpg_section/product.asp?product=1530&page=specs

 

[dabean]

Bringing this thread back to life ...

Looking at the Canon S100 which is considered to be a great camera - it has a 24mm-120mm (equivalent) F2.0-5.9. If they can do that in the compact camera, surely it wouldn't be *that* expensive or difficult to manufacture a 18-55 (F2.0 - 4.0)?

This little Olympus XZ-1 is 28mm-112mm F1.8-2.5 is even better http://www.olympusamerica.com/cpg_section/product.asp?product=1530&page=specs

Those compacts have tiny sensors, so much less glass to worry about. Why do you want a large aperture though? Gathering light or shallow depth of field? Small sensors aren't good at either.

A F2.8 lens on a full frame sensor gives the same depth of field as F2.0 lens on a crop body. Full frames are a lot better at high ISO as well.

 

[Dolby]

Taking photos of bands ... often low light conditions.

The lenses I use are both 2.8 - but lower would be ever better. I mean I could get a prime or two that are 1.8 or even 2.0, but it's just more convenient to have a zoom (even a small one) lower than 2.8

 

[dabean]

I don't know what camera you have but if it's a DX you might gain a stop of usable ISO with a FX. Read this:

http://yuen-kit-mun.suite101.com/best-low-light-digital-compact-and-slr-cameras-a218537
http://www.steves-digicams.com/knowledge-center/full-frame-versus-dx-cameras.html

I doubt you'll see faster zooms anytime soon.

 

[Edduck]

what camera are you using dolby? My 50D + Sigma 17-70 f2.8-4.5 handles low-light gigs perfectly. Yes I shoot at ISO1600 but it is so easy to remove noise now days anyway.

I do agree though, a f1.8 15-50 or something like that would be really handy, but I can imagine it would be a bulky and cumbersome lens!!

 

[Dolby]

I'm using a 7D and us a 70-200 2.8 ... and although I can't complain about the noise (I use 2500 or even 3200 on occasion), I want better I actually got Noise Ninja last night and will play with it tonight

I just thought the fact that these small camera's have a 1.8 lens at the short end - and zoom - means it could be done without being too heavy and expensive.

 

[fvdbergh]

I just thought the fact that these small camera's have a 1.8 lens at the short end - and zoom - means it could be done without being too heavy and expensive.

The Nikon Nikkor AF-S 70-200 mm f/2.8G ED VR II weighs 1540 g.

The Nikon Nikkor AF-S 200 mm f/2G ED VRII lens weighs 2930 g.

The 200 mm prime f/2 lens lists for $5300, compared to $2200 for the zoom. The prime lens only has 13 elements, the zoom has 21.

From this, I would guess that a 70-200 mm f/2.0 zoom would weigh over 3 kg, and cost over $5300, and have around 21 elements. It would be a fearsome beast.

So, as pointed out above: small sensors can get away with shorter focal lengths. Shorter focal lengths typically require physically smaller lens elements (less glass, smaller surfaces to polish and coat -> cheaper) to obtain large numerical apertures, compared to longer focal lengths**. This also explains why consumer zooms have decreasing apertures with increasing focal length.

**This does not apply to wide-angle SLR lenses, which require reverse telephoto designs to accommodate the mirror box between the sensor and the lens. Even for compacts, there would be a limit at which further decreases in focal length would start to increase lens complexity.