The more you extend the tripod, the more prone it is to vibration - collapse it
all, and use the tilt-screen while squatting. Self-timer also helps.
Amities
Philippe
> Le 11 mai 2020 à 21:37, Charles Geilfuss <charles.geilfuss@xxxxxxxxx> a écrit
> :
>
> Thanks for the info, Moose, and you could be right. I have only shot with
> it on a tripod (Manfrotto aluminum with Markins ball head). I've taken some
> pretty good images in the daytime, mostly wading birds, and as you point
> out the contrast is low. But that easy to fix in Photoshop. In moon shots,
> the image looks tack sharp in Live View and in the view finder but the
> images are soft. I use a two second delay but the mirror seems to induce
> camera shake. I may try mounting it on my telescope tripod which weighs
> about 35 pounds.
>
> Charlie
>
> On Sun, May 10, 2020 at 11:51 PM Moose <olymoose@xxxxxxxxx> wrote:
>
>> On 5/7/2020 1:28 PM, Charles Geilfuss wrote:
>>> I've been playing around with a recently acquired 600mm Vivitar Solid
>> Cat.
>>> Looking through it the images appear very sharp but camera shake is a
>> bear.
>>> Need to dig in the E-620 manual to figure out how to pre-fire the mirror.
>>
>> Are you sure it's that?
>>
>> 1. It's simply impossible to hand hold a 1200 mm eq. lens without IS, in
>> this case IBIS.The IBIS in the E-620 is an
>> early design, much less effective than later versions for µ4/3.
>>
>> DPR had this to say: "The E-620 doesn't have the top-tier IS system we saw
>> in the E-30 but Olympus is still confident
>> enough to claim a 4-stop advantage for this IS system (though our tests
>> have never shown an improvement on that scale)."
>>
>> And "As you can see, [50 mm lens] there's a clear 2 stop advantage to the
>> camera's IS system. While this isn't the best
>> performance we've ever seen, it's enough to drastically increase the
>> number of sharp, stable images you get."
>>
>> When I first started using two cameras around my neck in the field, one
>> was an E-M5, for the 75-300 zoom. The other was
>> an E-PM2 for the 12-50. I loved many aspects of the E-PM2, but in the end
>> it became obvious that the IBIS wasn't up to
>> the job, particularly for macro, which suffers from some of the same high
>> magnification problems as long tele.
>>
>> The review of the E-PM2 doesn't mention IBIS. I suspect that, 3.5 years
>> later, it's at least no worse than the E-620.
>> With an F8 lens, I imagine you've not been using really high shutter
>> speeds, either.
>>
>> 2. At that magnification, even the tiniest subject movement causes blur.
>> With the recent advent of Topaz Sharpen AI,
>> I've been impressed, occasionally amazed, at the improvement the Stabilize
>> Mode has made in images where I would have
>> credited some softness to lens quality and air movement.
>>
>> 3. Tripods are not all created equal. You may recall that Gary's lens
>> tests didn't look so good for the 600/5.6 and
>> 1000/11 OM Zuikos. He went so far as to use a lens support and/or two
>> tripods, with the tripod legs frozen into the rink
>> ice. He later said he had gotten much better results resting the lenses on
>> heavy sandbags on the roof of a car.
>>
>> Walt was an advocate of bags of shotgun pellets resting on top of camera
>> and lens. The common solution of hanging a
>> weighty bag from the camera center column is not nearly as effective,
>> especially with mid weight aluminum tripods.
>>
>> 4. Contrast! These lenses are low contrast. What we call sharpness is a
>> technically undefined idea that combines parts
>> of resolution, overall contrast and edge contrast. Take an image of a
>> Yin/Yang symbol, manipulate contrast so white
>> areas are 129 and black are 127, and it all appears to be neutral gray.
>> Yet, resolution is exactly the same as if black
>> is 0 and white 255.
>>
>> This effect is definitely going on with long shots with mirror lenses.I
>> am, coincidentally, working up a demonstration
>> of this on a moon photo. It's not so big a deal these days for those with
>> post processing abilities, but it was a big
>> deal in film days.
>>
>> The VivSCat is pretty low contrast. Here's a site where the guy summarizes
>> the old PopPhoto mirror lens tests and adds
>> his own MTF tests. Two of the mirror lenses I have, Sigma 600/8 and Oly
>> 500/8 are included, along with your Vivitar.
>> <
>> https://jimchungblog.com/2017/03/07/the-most-ultimate-mirror-lens-shootout-in-the-world/
>>>
>>
>> Low contrast tends to make photos look like they are not sharp.
>>
>> 5. Resolution. The PopPhoto tests make the Viv the lowest resolution, by a
>> fair margin. The MTF tests aren't as
>> different, perhaps a little lower than the Sigma 600. So it's not clear
>> just how low it is, but its resolution is
>> apparently not all that great. OTOH, I think my Sigma 600/8 is a pretty
>> good lens, on a solid tripod, remote release, no
>> wind, etc.
>>
>> Sooo . . . There are several factors that affect the final result, in some
>> combination or other.
>>
>> And . . . If you want a mirror lens, especially for hand held, the OM
>> 500/8 is the likely candidate.
>>
>> --
>> What if the Hokey Pokey *IS* what it's all about?
>> --
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>>
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