how much better is a f4.0 than an f5.6?

lifesdisciple · November 19, 2006

i have a quantarary 70-300mm f4-5.6 and was thinking of purchasing a sigma 100-300mm f4 and was wondering how much better this lens is over the one i have. sorry if it's a dumb question but its about all i have to spend and want to amke sure it is worth the money and the upgrade before i spend the cash.

Manfr3d · November 19, 2006

Hi,

you can read a technical review of both lenses here:

http://www.photozone.de/8Reviews/index.html

That should help you deciding on their quality.

jchin · November 20, 2006

Isn't the Quantarary are very low quality lenses? I've heard that somewhere in the past. The same goes for the Pheonix lenses.

Between Quantarary and Sigma ... I'd say Sigma has better quality glass.

lifesdisciple · November 20, 2006

jchin wrote:

Isn't the Quantarary are very low quality lenses? I've heard that somewhere in the past. The same goes for the Pheonix lenses.

Between Quantarary and Sigma ... I'd say Sigma has better quality glass.

I'm not sure who makes them but they are the Ritz Camera brand. i've had it for a while and it's not bad and i have a sigma and it is amazing. i was more curious about the f5.6 to f4 thing

Sam · November 20, 2006

lifesdisciple wrote:

I'm not sure who makes them but they are the Ritz Camera brand. i've had it for a while and it's not bad and i have a sigma and it is amazing. i was more curious about the f5.6 to f4 thing

Ok see if this help you.

The smaller the f number (the larger the aperture) alows more light to enter the camera, which in turn allows for a faster shuter speed, and a larger DOF.

A constant aperture lens is normally of higher quality then a variable aperture lens.

Most lenes are not at their sharpest wide open. Normally the best quality will seen stopped down a little.

The Sigma will give you about one stop (I think) advantage on the longer end over the Quantarary.

I haven't heard good things about the Quantarary lenses.

Fast glass is normaly considered to be f2.8 or smaller. f2.8 and smaller = $$$$

Sam

pathfinder · November 20, 2006

At the same ISO

f4 1/100th

but at f5.6 1/50th of a second

IE: 1 fstop faster at f4 than f5.6

Doubling the ISO will make an f5.6 lens as fast as an f4 lens with the lower ISO.

The real thing is not f4 better than f5.6, but is the lens optical quality and build quality better and that must be evaluated lens by lens. Generally folks are correct that Sigma has a higher reputation for quality than Quantaray.

Prime lenses are generally cheaper and better quality than zooms for a given dollar of purchasing power....

If you have a limited budget, you will be able to buy more quality per dollar with primes, but you will have to zoom with your feet then.

lifesdisciple · November 20, 2006

pathfinder wrote:

At the same ISO

f4 1/100th

but at f5.6 1/50th of a second

IE: 1 fstop faster at f4 than f5.6

Doubling the ISO will make an f5.6 lens as fast as an f4 lens with the lower ISO.

The real thing is not f4 better than f5.6, but is the lens optical quality and build quality better and that must be evaluated lens by lens. Generally folks are correct that Sigma has a higher reputation for quality than Quantaray.

Prime lenses are generally cheaper and better quality than zooms for a given dollar of purchasing power....

thank you. thats what i wanted to know:D

Red Bull · November 20, 2006

I say get the Sigma. I've used quantaray lenses, and they are some of the worst glass I've ever used. Not to mention very loud at focusing, flimsy, and very stiff/sticky zooming.

kres · November 20, 2006

In my experience, the Quantry stuff was pretty good back in the manual world - however they have never made an AF worth beans.

YMMV

mmroden · November 21, 2006

I remember reading that the quantarray lenses are just sigma lenses rebranded for Ritz. I don't have a link for that though, so my memory may not be serving me well. I wouldn't buy Ritz stuff anyway, they're overpriced compared to what you can get on the web.

Here's what I'd recommend: Do you really, absolutely, necessarily need the range? Seriously? Because if you have $100 to spend, and that's it, then getting a low end zoom will be fine. But if you have $100/month to spend, then save up for ten months and get a really nice lens. The difference will be like night and day. I got a 70-210 used for about $100 for the specific purpose of taking shots of my wife's marathons, and the shots could have been taken with a point and shoot camera as far as quality was concerned. They just looked bad. They served their purpose, but really, the lens just gathers dust now. Instead, I saved for an 85mm 1.8, and I've found that that's about the edge of the zoom range I really use anyway.

Your needs will vary, of course, and maybe you really like the long end. But consider:
$100 for starter lens. Decide it isn't good enough
$300 for prime lens. Decide it doesn't cover enough range
$500 for decent mid-price zoom. Needs VR or IS (depending on who's your manufacturer).
$800 got VR/IS to 200mm, and zoom to boot, but not really seeing a real jump in quality.
$1600 for 70-200 IS, and now you're taking shots that make everyone oooh and aaah, even if it's of garbage in the street.

Lens Lust is a dangerous disease, and it's cheaper to cure it by just going for the best lens in the class that you want rather than nickel and diming your way there.

Having said all of this, you may be a fantastic artist, capable of producing heartbreaking works of staggering genius with a pinhole camera and some string cleverly wrapped around a series of sequins and the bottom of a coke bottle. If that's the case, then go ahead and get whatever will serve your purpose. But just be aware of the potential progressions here...

claudermilk · November 21, 2006

One other thing to consider. When you are looking through the viewfinder, the lens is wide open, so a f4 lens will give you a brighter, easier-to see viewfinder than a f5.6 lens.

Personally, I would go straight to the Sigma & not even look at the Quantaray. They just don't have a good reputation. Like was jsut said, in the long run it's cheaper to save up a while & get the best lens you can to begin with (kind of the same idea as Thom's page on buying tripods).

Red Bull · November 21, 2006

mmroden wrote:

I remember reading that the quantarray lenses are just sigma lenses rebranded for Ritz. I don't have a link for that though, so my memory may not be serving me well. I wouldn't buy Ritz stuff anyway, they're overpriced compared to what you can get on the web.

I mentioned here that an employee at a Ritz Camera store tried to convince me that the Quantaray was the same as Sigma, but with a different name. It is NOT the same. When I tried out a Sigma 70-300 vs. the Quantaray 70-300, I could see a big difference in them. Definately not the same brand.

Doesn't matter to me now anyway, I decided to save up my money for a while and get a much much nicer lens, the Canon 70-200 f/4L. I'm VERY happy I did.

dangles · November 23, 2006

I have to agree with everyone about the Quantaray. The Sigma is a much better lens. I had a Sigma 50-500 and loved that lens but saved my money and bought the Canon 300mm f/2.8L IS. Get the best lens you can buy within your budget and you won't regret it.

how much better is a f4.0 than an f5.6?

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