Canon Community

Far-Out-Dude · ‎04-17-2023

I am not sure that I understand how to use these, I got the lens ordered on Saturday and have been reading the manual but these have me perplexed. Could somebody please help me to understand these direction. Thank you very much. This will be my first lens of this quality and for now will be attached to an eos M50 with the Canon Adapter.

rs-eos · ‎04-17-2023

I'll let others speak to Infinity Compentation.

For focus range limiting, that can be very useful to increase the speed of auto focus. e.g. if you know your subjects will always be 3 meters or further away, set the switch 3m - ∞. This prevents the lens from trying to focus on subjects less than 3 meters away.

If instead, you are taking images of subjects that will sometimes be closer than 3m, then set the switch to FULL. With the increased flexibility of capturing subjects at all distances (well, the minimum focusing distance will still apply), focusing can be slower since the lens is being instructed to operate on its full range of focusing distances.

--
Ricky

Camera: EOS 5D IV, EF 50mm f/1.2L, EF 135mm f/2L
Lighting: Profoto Lights & Modifiers

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jrhoffman75 · ‎04-17-2023

From B&H website:

When it comes to Canon’s autofocus lenses, the EF and EF-S lenses feature the focusing motors inside the lens barrels, not driven by the camera body. These internal motors are designed to be lightweight and power-consumption friendly, and do not provide enough torque to drive the traditional manual-focus helicoid mechanism.

Canon utilizes two different systems for manually focusing an autofocus lens: mechanical and electronic. In both cases, the autofocus drive system is disengaged from the focus system. Canon says that, in general, it is possible to incorporate hard stops into this system, but it would add considerably to the manufacturing cost of the lens for a feature with limited benefits.

For decades, the Canon FD and EF lenses have featured a variable infinity setting. Canon has two reasons for this:

Thermal expansion
Allowances for infrared photography

Canon is compensating for thermal expansion in its optics, not the lens body. Optical glass and crystal materials, such as fluorite, are known to expand and contract with ambient temperature changes. These changes are not seen with the naked eye, but can cause refraction of the lens surface and, therefore, change the infinity distance. This is more of a factor in longer focal lengths but, as Canon points out, many of today's wide-angle zooms are simply inverted telephoto designs and they can be affected by temperature changes.

John Hoffman
Conway, NH

1D X Mark III, M200, Many lenses, Pixma PRO-100, Pixma TR8620a, Lr Classic

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Far-Out-Dude · ‎04-17-2023

Thank you very much. Yes everyone has given great answers, the problem in understanding is mine, I have had very severe ADD/ADHD my entire life and I tend to have problems grasping things, for me one of the majors is anything with numbers, it is the reason I mess up my settings so often and struggle with DOF at times. Well most times which is why I take MANY photos at MANY settings.

FloridaDrafter · ‎04-17-2023

@Far-Out-Dude wrote:
Thank you very much. Yes everyone has given great answers, the problem in understanding is mine, I have had very severe ADD/ADHD my entire life and I tend to have problems grasping things, for me one of the majors is anything with numbers, it is the reason I mess up my settings so often and struggle with DOF at times. Well most times which is why I take MANY photos at MANY settings.

Look, these documents are written in Japanese and translated, so there is some loss in translation. I wouldn't beat myself up over it, LOL! Some of them absolutely take a lot of thought to try and figure out what the engineers are trying to convey. My wife, for a while, wrote software manuals and she did it from a users perspective and experience using the software. The programmers notes were not very helpful 🙂

Newton

Canon Community

I don't understand what these mean Canon EF 100-400mm f/4.5-5.6L IS II USM Lens