CANON 28 mm... waiting the answer from Jinfinance.....

Started Nov 6, 2012 | Discussions thread
Tom Caldwell Forum Pro • Posts: 32,325
Re: CANON 28 mm... waiting the answer from Jinfinance.....

Godfrey wrote:

Salvatore Castrovinci wrote:

About Jinfinance I am waithing his answer at my question to refound me or change the adapter with another one fully running also at the infinity marked in the lens barrel...... Actually the infinity that I can set manually is between 1,5 and 3 meters...... thanks at the focus mode 2 of the GXR. In this condition I cannot use the DOF scale in the lens.

That's a common problem, although your adapter seems a little further off than any of mine. Most are off such that the focus ring needs to be turned 4-5 mm to achieve infinity focus. On 25mm and longer focal length lenses, this isn't a big deal ... just make a new registration index on the lens and you can use the DoF scale and shift the focusing ring to suit. For very short lenses this is more of a problem.

Few of the inexpensive adapters are precise enough to be wholly trustworthy on the distance scale.

Of course, you also have to consider that the DoF markings on most lenses are intended for 35mm format. To get an approximate feel for the APS-C DoF with those markings, open up one stop, that is, if you set the focus zone for f/8 on the markings, open the aperture up to f/5.6 and that will achieve the correct DoF (approximately).

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Thanks Godfrey for that litle bit of information.  The dof scale has never bothered me a lot (but I do use it as a rough guide) - in my innocence I thought it would make no difference on 35mm lenses used on crop sensors.  I do find that mode2 highlight effect gives a pretty real indication of what part of the image might be in focus as well as the precise mid-point of focus.  I love the ripple-effect as you adjust focus.

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Tom Caldwell

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