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[OM] Re: WTB

Subject: [OM] Re: WTB
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Wed, 21 Feb 2007 14:58:22 -0500

Scott Peden wrote:
> 
> So, while on the subject, a shorter mirror lens will help to reduce the
> motion blur (assume it is the same amount of motion) because the distance
> tween the front element and the lens mirror is less, correct?

I wouldn't assume that, although the mirror lens being shorter overall 
*might* help reduce vibration.  I can also envision a case where the 
mirror lens has no tripod mount and the off-center weight distribution 
exacerbates vibration.  I don't think there's any simple answer.  If 
you're concerned about vibration you can up the ISO and the shutter 
speed and also add a beanbag on top as a damper.

> 
> I don't have the $250 to invest, but there is a 5.6 F Cassiegrain at the
> local camera shop I tried out, late, very late in the day, it was dark in 15
> minutes, and shots taken 1 block away were really quite acceptable, in fact
> better than the Seimar 500 in good light. I couldn't find the lens for sale
> at the manufacturer, but was told it was originally over 500 dollars (sales
> people, I don't always trust their pricing).

I suspect that what you're calling a Cassegrain is actually a Maksutov 
or Maksutov-Cassegrain (full name).  Same design as the Zuiko 500 and 
most other mirror lenses and spotting scopes of 90mm diameter or less. 
Steeply curved meniscus front element.  If what you're being shown is a 
500/5.6 Orion or Pro-Optic (Adorama brand name... same Chinese or Korean 
manufacturer, different name) the price is too high.  They didn't sell 
for that much brand new.  A 500/5.6 also has a large secondary mirror 
leading to a rather low image contrast.  Moose has suggested post 
processing the digital image to liven it up.  I have one of these beasts 
and intend to try that but haven't gotten around to it yet since I only 
recently got a T-mount for my Canyon.

Chuck Norcutt

> 
> -----Original Message-----
> From: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx] On Behalf
> Of Chuck Norcutt
> Sent: Wednesday, February 21, 2007 6:03 AM
> To: olympus@xxxxxxxxxx
> Subject: [OM] Re: WTB
> 
> Looks to me like the lens is performing pretty well.  Focus, motion blur 
> and vibration are probably more detrimental to your pics than the 
> quality of the lens.  What you're trying to do is hard no matter how 
> good the glass.
> 
> Chuck Norcutt
> 
> 
> Scott Peden wrote:
> 
>> Now, I want a sharper pic, Quantry is out, Oly is in, unless I can find a
>> real cheapy deal on a Tokina or Tamron. I'll keep this mail for later
>> shopping data Moose, thanks!
>>
>> http://www.flickr.com/photos/55838750@N00/sets/72157594514187851/
>>
>> Scott
> 
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