Glasses or not ......

To: Lyn Saint <>
Subject: Glasses or not ......
From: David Burren <>
Date: Sat, 16 Jul 2016 09:13:02 +0000
> On 16 Jul 2016, at 2:21 AM, Lyn Saint <> wrote:
> I have a bit of a quandary at the moment. I have acquired a Sigma 100-400
> mm lens for my Canon 7D and often find it difficult to determine if the
> bird is in focus or not. I can't see clearly enough through the lens.

The first question is whether you’ve been able to adjust the camera’s eyepiece 
to suit your eyes.
Not only do you want the subject to appear sharp through the viewfinder, you 
should also be able to see the exposure/etc information in the viewfinder!

> I have glasses but have also purchased and am using a dioptric adjustment.
> This is good but annoying as I need to have my glasses on to find the bird
> and then have to whip them off to focus though the lens.

On the upper right of the eyepiece (nestled behind the rubber) is a dioptric 
adjustment dial. Ideally you should be able to rotate that until the focus 
points and the numbers in the viewfinder are as sharp as possible. When doing 
this it’s easiest to put the lens on manual focus and DE-focus it so you’re not 
distracted by the image and can concentrate on whether the numbers are sharp. 
Then when it’s adjusted put the lens back to auto focus. At that point 
everything should be a lot clearer.

> For those of you who have this issue with glasses, do you have any advise
> on this issue?

I use mild reading glasses and can quickly adjust my eyepieces for either with 
or without the glasses. If the adjustment is not enough for you, Canon does 
have a range of dioptric adjustment attachments to change the range. But you 
still need to adjust that dial to suit.

One other point: I use and recommend the HoodEye eyecup attachments from 
HoodMan, especially the “glasses” models which have larger cups. They replace 
the Canon eyepiece and cups around the side of my glasses, giving good shading.
However one drawback is that it makes that dioptric adjustment dial a lot 
easier to accidentally bump (unless you tape it in place). So knowing how to 
quickly readjust that in the field is useful.

I hope this helps!
David Burren

> Frustrated,
> Lyn

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