Eh? You said "effective f-stop". I said "effective aperture". I
thought what I said was the same thing. I suppose you could infer that
my use of "aperture" related to the physical diameter of the aperture
but the word "effective" sort of rules that out. And if you return to
my original post at bottom I spoke of being able, at half life-size, to
focus at an effective f/3 (using the f/2 lens) instead of an effective
f/5.3 using the f/3.5 lens.
Chuck Norcutt
On 12/15/2010 6:24 PM, Jim Nichols wrote:
> I rationalize it the other way, Chuck. The physical aperture stays the
> same, but the actual lens-to-sensor distance must be substituted for the
> original FL. Then, the lens-to-sensor distance is divided by the aperture
> to get the effective f-stop. These measurements don't require a lot of
> accuracy. Fortunately, I can just set the selector to "A" and the camera
> does all of the work for me.
>
> Jim Nichols
> Tullahoma, TN USA
> ----- Original Message -----
> From: "Chuck Norcutt"<chucknorcutt@xxxxxxxxxxxxxxxx>
> To: "Olympus Camera Discussion"<olympus@xxxxxxxxxxxxxxxxx>
> Sent: Wednesday, December 15, 2010 4:05 PM
> Subject: Re: [OM] So here's the deal...
>
>
>> Eh? This ain't got nothing to do with digital or sensor sizes. Have
>> you had meters in your cameras for so many years that you've forgotten
>> all about exposure adjustments for magnification when shooting macro?
>> The effective aperture is reduced and the image becomes dimmer. Go read
>> the Oly bellows manual for your punishment. :-)
>>
>> Chuck Norcutt
>>
>> On 12/15/2010 4:23 PM, Andrew Fildes wrote:
>>> I thought we'd dealt with that one recently.
>>> The view is smaller, not dimmer.
>>> An aperture is an aperture is an aperture.
>>> The sensor size does not affect it.
>>> If I put my Zeiss 180mm f2.8 medium format lens on 35mm, it does not
>>> become an f2.
>>> I can put it on my E-P2 and have done for fun. Does it become an f.1.4?
>>> No.
>>> My Voigt. 25mm f0.95 is still that aperture on mFT.
>>> It's DOF that is affected.
>>>
>>> Andrew Fildes
>>> afildes@xxxxxxxxxxxxx
>>>
>>>
>>>
>>> On 16/12/2010, at 12:31 AM, Chuck Norcutt wrote:
>>>
>>>> But the reason for an f/2 macro lens is not for you to shoot at f/2.
>>>> It's so you can still focus at an effective f/3 instead of f/5.3 when
>>>> you're at half life-size. That said, I only have the f/3.5 version.
>>>> f/2 is too expensive. :-)
>>>
>> --
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>>
>
>
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