No, the shots were not taken at the same distance as the "film" sizes are
different. The one with E-PL1 was talken at a longer distance so that they
have the same coverage angle. Here shown the DOF difference of the same lens
under same aperture and "final magnification". It is obvious that their
degree of out focus are differ, hence it is the sensor size not the focal
length make the difference.
I'm more interested on apparent DOF rather than the calculated one. Just
like the diffraction talk, it isn't as important as some people think, it
was shown on the 90/2 samples I posted before, the difference between F4 and
F22 was nothing dramatic.
C.H.Ling
----- Original Message -----
From: "Chuck Norcutt" <chucknorcutt@xxxxxxxxxxxxxxxx>
>I can't argue with the results and it's clear there's something I don't
> understand if you tell me these two 80mm shots are taken at exactly the
> same distance. In particular, at f/8 the 12MP 4/3 sensor should already
> be beyond diffraction limits on the green and red channels. At f/8 the
> 5DII is also beyond diffraction limits but only on the red channel.
>
> Ah! Some partial enlightenment. Since this a macro shot, and perhaps
> at close to 1:1, the marked aperture bears not much relationship to the
> effective aperture. So the effective aperture is smaller than f/8 and
> both cameras are beyond diffraction limits in these images. But that
> still doesn't help me much.
>
> Chuck Norcutt
>
>
> On 12/19/2010 2:07 AM, C.H.Ling wrote:
>> Here are two samples taken with Zuiko 80mm F4 at F8:
>>
>> 5D II, cropped both edges to make it 4:3 and scale down to 4032x3024
>> (same
>> as E-PL1):
>>
>> http://www.accura.com.hk/IMG_0948c.jpg
>>
>> Olympus E-PL1
>>
>> http://www.accura.com.hk/PC193332.jpg
>>
>> You can see the apparent DOF on the second one looks deeper, it will be
>> more
>> so with smaller sensor.
>>
>> C.H.Ling
>>
>> ----- Original Message -----
>> From: "C.H.Ling"<ch_photo@xxxxxxxxxxxxx>
>> To: "Olympus Camera Discussion"<olympus@xxxxxxxxxxxxxxxxx>
>> Sent: Sunday, December 19, 2010 1:21 PM
>> Subject: Re: [OM] Jeweler's camera
>>
>>
>>> You said it is the focal length not the sensor size cause different DOF,
>>> so
>>> consider the same sensor - FF for example. The DOF of 100mm lens at 10
>>> feet
>>> is 1.42ft, the DOF of 50mm lens at 5 feet (to get the same mag.) is
>>> 1.44ft,
>>> it is almost the same as the 100mm lens.
>>>
>>> C.H.Ling
>>>
>>> ----- Original Message -----
>>> From: "Chuck Norcutt"<chucknorcutt@xxxxxxxxxxxxxxxx>
>>>
>>>
>>>> That's not what my DOF calculator says. If you can quantify it with a
>>>> specific example I'll believe it. But I don't think you can. The
>>>> example I used was a 100mm lens at f/8 focused at 10 feet with a CoC of
>>>> 30 lines/mm. That yields a DOF of 1.58 feet. Then a 50mm lens at f/8
>>>> also focused at 10 feet but with a CoC of 60 lines/mm. That's to allow
>>>> for a smaller image size (sensor) to be blown up twice as much as the
>>>> 100mm shot such that the final print size (magnification) is the same.
>>>> The 50mm lens gets a total DOF of 3.28 feet. Slightly more than
>>>> double.
>>>>
>>>> Chuck Norcutt
>>>>
>>>> On 12/18/2010 8:32 PM, C.H.Ling wrote:
>>>>> I do think it is the sensor gives the increased DOF not the lens, for
>>>>> the
>>>>> same magnification, a 50mm lens and 100mm lens have the same DOF under
>>>>> the
>>>>> same aperture but the one with smaller sensor gives deeper DOF.
>>>>>
>>>>> C.H.Ling
>>>>>
>>>>> ----- Original Message -----
>>>>> From: "Chuck Norcutt"<chucknorcutt@xxxxxxxxxxxxxxxx>
>>>>> To: "Olympus Camera Discussion"<olympus@xxxxxxxxxxxxxxxxx>
>>>>> Sent: Sunday, December 19, 2010 12:46 AM
>>>>> Subject: Re: [OM] Jeweler's camera
>>>>>
>>>>>
>>>>>> It's the short focal length that gives the increased depth of field,
>>>>>> not
>>>>>> the sensor. But small sensors and short lenses do go together.
>>>>>>
>>>>>> Chuck Norcutt
>>>>>>
>>>>>>
>>>>>> On 12/17/2010 11:33 PM, Andrew Fildes wrote:
>>>>>>> Yes, the compact size sensor on the G12 gives a deeper DOF and I
>>>>>>> forgot
>>>>>>> to mention - articulated screen. Don't do macro without one!
>>>>>>> I'd imagine a tabletop set up with cube. mini-lights and table
>>>>>>> tripodfd
>>>>>>> for very small items, all easily repeatable on a budget. I like to
>>>>>>> put
>>>>>>> a
>>>>>>> small box in there and drape it with velvet offcuts for bright
>>>>>>> jewellry.
>>>>>>> The cube tents usually come with a drop-down front panel with hole
>>>>>>> for
>>>>>>> lens. Good for anything shiny but also for any small and colourful
>>>>>>> object.
>>>>>>> Andrew Fildes
>>>>>>> afildes@xxxxxxxxxxxxx
--
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