70-300L vs. 100-400II IQ?

Started Dec 24, 2016 | Discussions thread
TheBlackGrouse Senior Member • Posts: 2,236
Re: 70-300L vs. 100-400II IQ?

Steve Balcombe wrote:

TheBlackGrouse wrote:

Steve Balcombe wrote:

TheBlackGrouse wrote:

BirdShooter7 wrote:

When you say the 100-400 is more noisy do you mean the AF motor makes more noise?

Oh sorry, wrong expression probably, I'm not a native speaker.

We're talking about 'random variation of brightness or color information' (Wikipedia).

At close distance both lenses produce (almost) noise free images (up to ISO 1600 on a 7DII). But at longer distances my 100-400II gives images with less noise and they are more easy to clean.

Different noise levels, same camera, same sensor, that didn't make sense to me at first.

But the resolving power of the lens seems to play a role. I'm very careful because this is difficult terrain when you are not a technician.

It's impossible for different lenses using the same settings to affect how noisy an image is. It's also impossible for shooting distance to affect image noise.

Some other more subtle factor is at play here, such as the shorter lens including more sky in the shot which might result in shorter exposures if not compensated for. The slightly underexposed image might then show more noise when processed. This is a complete guess of course - the only thing I can say for sure is neither the lens nor the focusing distance can directly cause noisier images.

Interesting. Thinking about subtle factors, is it possible that the 100-400II has a slightly better light transmission resulting in less noise?

If you were conducting a formal test, taking the same shot with both lenses using the same manual settings, you might find a very small difference in the actual exposure due to a T-stop difference, but I'd expect it to be very slight as these lenses are of similar complexity. That can't directly affect noise, but processing the darker image might potentially increase noise. Even then, I'd be very surprised if it was noticeable. What's more, in normal use using Av mode (etc.) the metering should even out the exposures so there would be no difference at all.

We are talking very subtle/picky and probably almost invisible differences here.

And could that be more visible on images made at longer distances, because they need a bit more post processing?

If you are sharpening them more as a way to compensate for haze, for example, then possibly yes. I'd say that's a very credible possibility.

Thanks, couldn't believe it myself so I asked some pros a few weeks ago. They mentioned the resolving power. These are both modern lenses, so the differences must be subtle. But all small differences together can have some effect on image quality.

After working with my 70-300 L for five years I knew what to expect. So, when I started with the 100-400II I noticed it immediately at larger distances, with record shots of birds at hundreds of yards and more. Not exactly standard use.

It never bothered me, the 70-300L is great and will not be sold. Ok, you give up the 100 mm extra but It 'gives' you two extra lenses when going out: a 70mm and an extra wide angle or macro.

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