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[OM] Re: E-500 or E-1 - (5D dust)

Subject: [OM] Re: E-500 or E-1 - (5D dust)
From: "Joel Wilcox" <jfwilcox@xxxxxxxxx>
Date: Sun, 9 Apr 2006 12:52:54 -0500
On 4/8/06, Wayne S <om4t@xxxxxxxx> wrote:
> Dust issues need to be qualified by whether the photographer typically
> uses a high F stop or not. Dust is not usually visible at lower F
> stops. Since DOF of a full frame sensor at F16 is similar to the E-1
> sensor at F8, higher F stops are going to be used more often with a
> Full Frame sensor than a 1/2 sized E-1 sensor.

Does this also mean that dust on an E-1 sensor at f16 would be twice
as bad a problem image-wise as for a D5 at f16?

> Dust must really be a
> bugger for medium format backs.
>
> I've been using a Canon 5D since October. I have run into the dust
> issue. I have an OK solution for the dust and my 5D. (below)
>
> Dust on the 5D is just like any camera, it depends on the F stop used
> to make it visible. If the photographer shoots at F11 or above
> then the shadow of the dust will be sharper, and more of a problem. So,
> we need to qualify dust problem reports with F stop used. If the
> photographer shoots a lot of macro, then dust is going to be a problem.
> For example here is a macro shot with the 5D:
> http://www.photosig.com/go/photos/view?id=1722932

Gorgeous!

> If you look close, you can see specs of dust. I made no attempt to
> remove them. So, if you shoot at F16 a lot, any camera will have a
> problem, including the E-1. And the larger the sensor the more
> likely a high F stop is used and will show dust.
>
> -dust solution-
> My solution to the 5D dust is a quick spray with a "CO2 Duster".
> This gets rid of 80-90% of the dust. Sometimes some dust is stubborn
> and I have to do the next step. (E-1 has same problem with this
> remainder dust, as it sticks. These are usually the smaller specks.)
>
> On occasion, I use a PecPad wrapped around a thin cut plastic (made
> from stiff bubble pack plastic, the flat sections. You know, the
> packages you can hardly open and nearly slice you finger off when
> trying?). For the 5D I make it about 22-23mm and taper down from there.
> Then I wrap a PecPad at the wide end, careful not to make it too thick
> on the edges as that limits the ability to wipe next to the edge of the
> sensor. This is done by folding and taping the PecPad with minimal
> wrapping around the edges of the plastic. Keep oily fingers away from
> the wiping edge when wrapping.
>
> Next, use 2 drops of methanol, wipe immediately in one direction, one
> time only. Then a couple of blasts with CO2 duster to get the loose
> stuff out. Most of the time is spend taking a picture of a blue screen
> monitor and loading into the computer to see if I got it all. Repeat
> if necessary, once you get the hang of it, once is usually enough.
> -*-

OK, it's great that you have a good methodology, but yikes!  I've got
dust from my recent trip to Arizona and Utah on the mirror and/or
screen of my E-1 so thick it looks like the Hawaiian archipeligo in
the viewfinder and I don't see any evidence of dust on the sensor at
all!  I just stepped out back and shot the western sky at f16:

http://myweb.uiowa.edu/jfwilcox/E-1_dustatf16.jpg

Image shot at HG quality mode, ISO 100, saved for web at 50% quality
jpg. I don't see a problem.  Did I do something wrong?

> Because F stop determines the visibility of dust, any data as to
> whether dust is a problem, you have to ask, "at what F stop" or you
> will not get a meaningful correlation between different peoples
> experience with dust. But the dust is not unmanageable. The CO2
> duster takes care of 80-90% of the problem for me, and is quick
> and easy to do in the field.
>
> Low noise is a nice feature of the 5D. Here is a shot at 1600.
> http://www.airsprite.net/5D/w6x9_MG_2861.jpg
> and 100% crop of that shot:
> http://www.airsprite.net/5D/w_100crop_MG_2861.jpg
> F5.6 at 1/10sec, 173mm with IS.
> Here is another shot, 1600, F4, 1/2sec, 24-105 IS lens @60mm
> http://www.airsprite.net/5D/wM_MG_3006.jpg
> all shots handheld, and taken here:
> http://www.airsprite.net/5D/wRoll_6x9_MG_2848.jpg
> 1600, F5.6, 1/15sec, 50mm 5D
>
> So, if you like high ISO shooting, ...
>
> WayneS

Those are delightful shots and I know the E-1 can't do as well,
particularly measured item to item at higher resolutions.  I think the
E-1 could match those web images at ISO 1600, however, with a lot less
post-process fuss than it takes you to clean your sensor (an
irrelevant comparison, but you get the point). If the workflow demands
fast turnaround on high rez images and the need for speed is
paramount, I think we know the horse and the course.  If it is more
rarely used and mainly for sending web images to Grams, then the E-1
will more than do IMHO.

The supreme value of the D5 to me would be to shoot fullframe.  I
don't mean to be contentious about the noise issue, but it's blown out
of proportion to its real significance.  I know that is probably a
statement about which we will (amicably I hope) disagree forever and
anon.

Joel W.
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