Is this true? (Technical question)

[Sime]

WHAT!... you mean I didn't need to spend all this money on L series lenses!!... bwa ha haaa

I think your question has been answered very well, above.

S

[AlphaBjerke]

The same discussion is going on over on my flickr group. One of the theories posited is that the better glass, with it's better coatings focuses more light on the sensor. It seems like this thread has decided that is hogwash, but if you are interested in a different thread talking about the same thing...

http://www.flickr.com/groups/sony_al...57616625114347

[Jim Bryant]

Focus speed

The biggest advantage of Canon lenses over third party ones is not as much the image quality as the Ultrasonic motor (USM). As a generalization, we can state that all Sigma and Tamron lenses are slower to focus than their USM powered counterparts.

How much of a problem is this? It depends. If you are mostly shooting static subject or you are in a controlled environment, you couldn’t care less. On the other hand anything related to sport or wildlife photography requires instant focusing.

In either case, if you are planning to use the lens mostly for cinephotography, it should not be an issue since you will use the manual focus anyway.In this case, just make sure the focusing ring rotation is smooth and fluid.
Internal focusing/zooming

This is one of these things that you don’t notice until it is gone. Basically, it prevent the front of the lens to rotate or moves when you zoom or focus. While this might not seem like a big issue, it is quite important when you are using grad filters. It is a small annoyance when taking pictures, but a big deal when shooting movies. So according to your need you might want to watch this carefully.

Built quality

Canon might charge a premium for its lenses but at least a small part of it is spent toward better quality material. While a plastic enclosure might not have an effect on the quality of the picture, it has a better resistance to shock and scratches. Also, from personal experience I can say that I have never seen a broken metal lens while I have seen countless plastic ones which had a defect of some sort.

While most high end third party lenses have a very good built quality, it is just not as good as the one from Canon. I am thinking here about weather sealing (water and dust). But then again, unless you are planning to drop your lens on the ground, it should not be that much of an issue!
Image quality

Yes, it is true, generally speaking third party lens image quality is lower than the Canon equivalent model. How much lower? It depends. In some case there is not much differences and for others, it is drastic. This is why I created a list of premium third party lens (coming very soon!). While the lenses on this list might not have all the bling and coolness of their Canon counter part, they have identical (or better!) image quality which make them great buys.

Sigma, Tamron, Tokina and several other manufacturers make autofocus lenses for Canon EOS cameras, so why not use one of them? Well, the main reason is that in general the Canon lenses are of higher quality and are more compatible. If there's a problem and you have a Canon lens and a Canon body, then there's no doubt that it's Canon who will fix the problem. If you have a Sigma lens on a Canon body, who has responsibility for them working together? There are also a lot of examples (especially with Sigma lenses) of older lenses not working on newer EOS bodies. Often the lens maker can "rechip" the lens and make it work, but can you depend on that?

Of course 3rd party lenses are often cheaper and some lenses made by 3rd party manufacturers just aren't made by Canon (e.g. Sigma's 15-30 zoom and 50-500 zoom), so if you want one of those lenses, you don't have a lot of choice but to go 3rd party. Many people are quite happy with 3rd party lenses and equally happy to have saved some money by buying them. So I'd recommend sticking with Canon if Canon make the lens you want at a price you can afford. If they don't, then 3rd party lenses are always an option.

[vandergus]

he said that the clarity of the more expensive glass itself--not a larger aperture--allowed him so shoot at a lower ISO. He compared it too there being different grades of diamonds with the better rated ones having more clarity.

Now that is a load of crap.

I've heard of coatings allowing for better light transmission but it usually doesn't amount to more than 1/3 of a stop.

Focus speed.....
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Stay on target... Stay on target...

[vandergus]

Someone on the flickr thread brought up differences in real world ISO values, which sounded plausible except that, according to the DXO website, your Sony sensor was measured to be similarly if not more sensitive than Canon sensors at a given ISO setting. So if anything, he should have to shoot at a higher ISO to get an equivalent exposure.

[LoveDSLR]

Originally Posted by AlphaBjerke

One of the theories posited is that the better glass, with it's better coatings focuses more light on the sensor.

L lenses transmit better 'quality of light' but with same quantity.

[AlphaBjerke]

Ok, I don't have a horse in this race, I am just curious and now that I have people in two different forums involved in the debate, I REALLY want to know what is what. Someone out there has a cheap kit lens and a high end lens so why don't you do the experiment and see? Take the exact same shot in the exact same conditions at the exact same settings and see! How hard can it be? End of debate, right?

[candleman]

What exactly was his exif???
Focal length & metering mode included…

I’m willing to bet you were using different metering modes. ...

Theres is no way “glass quality & coatings” will make 1 stop difference. (ISO 200-400)

my money is on ~ you were exposing differently
simple as that.

[jprime84]

Originally Posted by AlphaBjerke

While shooting the other day, I met a fellow shutterbug who told me that with the higher end lenses--for instance, the Canon L Series--you can shoot at a lower ISO because more light gets through the better glass. (And Mike, if you joined DPS like I suggested, I don't doubt you, but someone else didn't go for what you said so I'm just throwing it out there)

Specifically, he had an expensive lens and I had a kit lens. We were both shooting at the same aperture and the same shutter speed, but he was able to shoot at 200 ISO when I had to shoot at 400 to get the same settings.

What do you folks know about this. It sounds logical to me!

- First off, your friend's reasoning is certainly bogus

- Assuming that you were both manually manipulating the aperture and shutter speeds while leaving the ISO to "auto," you may have had another setting that was different that could affect ISO such as the metering mode (spot, center biased, evaluative, etc).

If you decided to say that every setting was the same, it can still come down to software. Software in the Canon determines what ISO it wants to use given a set of variables. Separate software in the Sony does the same thing, but its unlikely they were written by the same people.


Probably the most confusing part of your statement, is your wording is unclear. When you say that "We were both shooting at the same aperture and the same shutter speed" do you mean you both manually made input those settings?

"he was able to shoot at 200 ISO when I had to shoot at 400 to get the same settings"
This makes it sound like ISO was the manual setting, and the others were automatic? You can set any of these settings, including ISO, to whatever you want.

Only real way to find out what was up was to get EXIF data

[autofocus]

Folks, Correct me if I'm wrong, but his $3000 camera has a bigger, better, and more light sensitive sensor than your camera...larger sensors have larger pixels, and can handle low light situations better than the smaller ones...and certainly handle digital noise better...that's one of the things your paying for when you buy a $3000 camera. All that said, his camera (body) may be able to properly expose an image better in the same conditions than your camera, and the particular lens should be much less of a factor.