From: DanP on
On 26 May, 17:49, infiniteMPG <57clas...(a)gmail.com> wrote:
> > Don't pay attention to him. Enjoy your toy and learn its strengths and limitations. My suggestion is try to weight your tripod to minimize shake and shoot at as high a speed as you can.
> Last night I used the 1600 setup and snapped some pix of the moon.
> Then I swapped it out for my  Tamron AF 18-250/3.5-6.3 DI II Macro
> Lens, zoomed in as tight as I could and snapped some more.  Then
> swapped that out for my Tamron SP AF90mm F/2.8 Di Macro Lens with a 2X
> doubler and snapped a few more.  Downloaded them and looked.  With the
> 1600 the moon could just barely fit in the frame.  I was really close
> to good clear focus and think I'll do better when I get my 2.3x Finder
> Magnifier (and maybe adjust my view finder better).  The moon with the
> 18-250 pushed to 250 was a button in the middle of the frame and when
> zoomed was pretty bad looking.  With the 90 (actually 180 with the
> doubler) the moon was pencil eraser sized and not any good when zoomed
> on.

Can you please upload those pictures? Shooting the moon is a good
benchmark for lenses.


DanP
From: infiniteMPG on
> Can you please upload those pictures? Shooting the moon is a good benchmark for lenses.

Did that but that's where I started seeing lack of detail no matter
what I did. I think my experiment is about over with the 800mm. This
is what I set up a few days ago and tried.

I rolled my big arsed gas grill over to the door of my back porch,
nice sunny afternoon so plenty of light. I set the camera and lens on
the rigid side table on top of a bag of mortar mix I had sitting
there, this allowed me to form a nest for the camera and lens. I then
laid weight on top to keep things steady. I aimed at a tree about 100
feet away so I had good distinct lines in the bark and the edge of the
tree. Using my remote I took several pictures and regardless of
shutter speed I got blurry edges on every shot. I tried different
settings but couldn't get crisp focus on anything. I then turned my
focus on a fence post corner about 150-feet away. Same kind of
results.

I had ordered a 2.3X view finder magnifier which I had also just
received and I tried that thinking I could focus better but since this
is an 800mm lens, I could not get this to bring the image in the view
finder in to focus. I am thinking that it's not meant for such long
lenses so I'll play with that later.

Looking thru the view finder with the 800mm I was seeing a totally
crisp image, well defined edges, but what I ended up with pictures of
was fuzzy shots with no crisp edges.

So if someone has some settings to try like if I should be working in
just shutter speed or fully manual or what settings to try I'll be
more then happy to try before I stick a fork in this. I think
aperture mode is useless since this is a fixed f8.0 lens.

ANY SUGGESTIONS or this experiment will soon draw to a close. If I
can't get clear shots on a sunny day with tons of weigh holding the
lens steady I sure don't think sticking it on a tripod or manually
holding it will ever work.

Thanks :O/
From: David Ruether on

"infiniteMPG" <57classic(a)gmail.com> wrote in message news:ce98d6fd-1a70-42c9-9e15-a8f4869abdfd(a)i31g2000yqm.googlegroups.com...

>> Can you please upload those pictures? Shooting the moon is a good
>> benchmark for lenses.

> Did that but that's where I started seeing lack of detail no matter
> what I did. I think my experiment is about over with the 800mm. This
> is what I set up a few days ago and tried.
>
> I rolled my big arsed gas grill over to the door of my back porch,
> nice sunny afternoon so plenty of light. I set the camera and lens on
> the rigid side table on top of a bag of mortar mix I had sitting
> there, this allowed me to form a nest for the camera and lens. I then
> laid weight on top to keep things steady. I aimed at a tree about 100
> feet away so I had good distinct lines in the bark and the edge of the
> tree. Using my remote I took several pictures and regardless of
> shutter speed I got blurry edges on every shot. I tried different
> settings but couldn't get crisp focus on anything. I then turned my
> focus on a fence post corner about 150-feet away. Same kind of
> results.

Air quality can affect results even at these "close" distances. Also, if
*you* move at all on the porch during the exposure, that also could
easily spoil results. Also, as I pointed out earlier, few mirrors are
actually very good, and even the likely best vary considerably...

> I had ordered a 2.3X view finder magnifier which I had also just
> received and I tried that thinking I could focus better but since this
> is an 800mm lens, I could not get this to bring the image in the view
> finder in to focus. I am thinking that it's not meant for such long
> lenses so I'll play with that later.

It should make no difference - but this is a good indication that the
mirror itself is poor (among other possibilities). BTW, most SLR
eyepiece camera viewfinders have low magnification (well below 1:1),
so things can look sharper in the finders than they are in reality.

> Looking thru the view finder with the 800mm I was seeing a totally
> crisp image, well defined edges, but what I ended up with pictures of
> was fuzzy shots with no crisp edges.

See all the above...

> So if someone has some settings to try like if I should be working in
> just shutter speed or fully manual or what settings to try I'll be
> more then happy to try before I stick a fork in this. I think
> aperture mode is useless since this is a fixed f8.0 lens.

Aperture-priority or manual mode is usually appropriate for mirrors since
they have no adjustable apertures.

> ANY SUGGESTIONS or this experiment will soon draw to a close. If I
> can't get clear shots on a sunny day with tons of weigh holding the
> lens steady I sure don't think sticking it on a tripod or manually
> holding it will ever work.
>
> Thanks :O/

You may be surprised with hand-holding, *IF* the mirror is sharp,
*IF* the subject is reasonably close (and the air quality is EXCELLENT,
which means shooting early in the day with CLEAR air, and not over rooftops,
paving, etc.), and *IF* you can focus well and hand-hold this rig steady
(it may take many tries with the same photo...). Try chimney bricks and
roofing materials in bright light with the ISO set as high as you dare to see
if you can get your first sharp image. If not, there may be a buyer on eBay
for the mirror...;-)
--DR


From: infiniteMPG on
Thanks for the info and similar conclusions as I am drawing,
especially the eBay one. I wanted the lens mainly for tripod use for
things like some nearby eagle's nests. Not much use to me as a lens
to carry and hand hold, too bulky and too big a focus ring to hold by
hand and focus. I'll push the ISO and see what I can do with that.
When I do macro I do aperture and it works great but with fixed it's a
whole new game. How would I use aperture priority with a fixed
aperture lens?

Another thing I was curious about is if the view finder is focused
properly for my eyes. Since how my eye is seeing something in focus
and how the CCD sees it might be two different things. Since this is
very focus intense I am wondering if small differences there can make
a difference. How do you assure that the view finder is focused
correctly? With manual focus lenses I can see this being extremely
critical.

Thanks again.
From: David Ruether on

"infiniteMPG" <57classic(a)gmail.com> wrote in message news:9afec37c-f752-42f8-b421-70ecaa1584f3(a)i28g2000yqa.googlegroups.com...

> Thanks for the info and similar conclusions as I am drawing,
> especially the eBay one. I wanted the lens mainly for tripod use for
> things like some nearby eagle's nests.

So long as the light is bright enough, you are close enough, the
tripod is steady enough through the exposure time, the lens is good
enough, and you can focus well enough, this, ahem..., *should* work...;-)

> Not much use to me as a lens
> to carry and hand hold, too bulky and too big a focus ring to hold by
> hand and focus. I'll push the ISO and see what I can do with that.
> When I do macro I do aperture and it works great but with fixed it's a
> whole new game. How would I use aperture priority with a fixed
> aperture lens?

Usually the camera defaults to a given (not necessarily specified)
aperture with a mirror which has no diaphragm or aperture connections
to the camera's mechanics/electronics (with Nikon, the default is f5.6...).
In aperture mode, the camera then adjusts the shutter-speed/ISO for
correct exposure given the light level sensed through the lens (same for
manual exposure - you adjust shutter-speed, and/or aperture, and/or
ISO setting for correct exposure, however this is indicated by your
camera's metering system). It doesn't matter what the actual aperture is,
except in terms of the other two parts of the exposure triad required to
get it right without going outside of the range of practical values.

> Another thing I was curious about is if the view finder is focused
> properly for my eyes. Since how my eye is seeing something in focus
> and how the CCD sees it might be two different things. Since this is
> very focus intense I am wondering if small differences there can make
> a difference. How do you assure that the view finder is focused
> correctly? With manual focus lenses I can see this being extremely
> critical.
>
> Thanks again.

Agreement between VF focus and sensor focus is not so critical with very
long lenses as it is with very short lenses (long lenses have relatively little
DOF, but relatively great depth of focus, which can cover small errors - but
the reverse is true with wide-angles, which have relatively greater DOF,
but relatively far less depth of focus, so the agreement between the sensor
focus and screen focus with WAs is more critical for good manual focusing).
Also, if you see a sharp eye-level screen image on the ground-glass VF area,
your eyepiece focus adjustment is properly made (I prefer using wide-angle
lenses for making this adjustment, and also for checking screen/lens/camera
body alignments).
--David Ruether
www.donferrario.com/ruether
d_ruether....@....hotmail.com