A7r - and why I'm keeping it ...

[mjm6]

Re: Shutter Shock at 784 mm in Portrait Mode!

Do we know in which direction the mechanical shutter moves in the A7R?
Up or down? Or sideways?
Thanks for a reply.

K-H,

Looks pretty clear that the shutter moves up/down if I read your post above correctly.


The camera mounting arrangement you show in the photo is not ideal... While there is a lot of metal there, it is all still at the mercy of the rigidity of the ball and mounting plate that is many inches away from the camera. You are relying on a 'rigid frame' or 'moment frame' approach to solve the problem, rather than the (typically) far more efficient 'braced frame' approach.

EQE Reference Center

STRUCTUREmag - Structural Engineering Magazine, Tradeshow: A Solution to Seismic Bracing Restrictions

The top link shows a rigid frame approach, and the second shows a braced frame approach. The exact same problems are inherent in a camera are occurring in structural steel.

Not Good, in fact this example looks almost completely useless, because of the hinges:
http://www.sunwayfoto.com.cn/uploadfile/CKEditor/TLS-00.jpg

Much better:
Manfrotto 359 Long Lens Support (MN359-1) - Wex Photographic

Your photo shows a system somewhere between these two in usefulness, because the Arca bar is rigid, but you are still at the mercy of the rotation point of the ball mount and a few small metal parts on the head, and also flex in the frame.

You might get a more rigid mount by moving the frame over the ball head somewhat, but that will probably mess up the balance of the camera and lens. This will shorten the moment-arm from the head to the camera, and also reduce the distance through which the arca bar has to flex (think of the arca like a stiff fishing rod, while it doesn't appear to, it has the ability to flex like a rod when unsupported, but if you affix it at the middle rather then the end, it's flexure will go down by about 3/4).

The manfrotto approach is FAR, FAR more effective, because it sets up a braced frame.

For reference, I'm a photographer, but also an architectural engineer. However, I have never played a doctor on TV, hahaha...



---Michael

EDIT: Made some edits to aid in clarity...

 

[k-hawinkler]

Re: Shutter Shock at 784 mm in Portrait Mode!

Hi Michael,

Thank you so much for your feedback. All excellent points.
I have the Manfrotto 359 Long Lens Support on order.
If the shutter moves indeed in the A7R vertically then the Manfrotto 359 Long Lens Support should help in Landscape mode.
However, in portrait mode that would be different, as then the shutter kicks sideways, wouldn't it?
Thanks again.

 

[mjm6]

Re: Shutter Shock at 784 mm in Portrait Mode!

Hi Michael,

Thank you so much for your feedback. All excellent points.
I have the Manfrotto 359 Long Lens Support on order.
If the shutter moves indeed in the A7R vertically then the Manfrotto 359 Long Lens Support should help in Landscape mode.
However, in portrait mode that would be different, wouldn't it?
Thanks again.

K-H,

Yes, in portrait mode, you will still have problems.

I think you were having SOME problems in landscape mode, but the image didn't happen to have any ideally oriented lines to see it as well as the portrait mode ones (mostly vertical lines of the crane). However, look at the background, and it appears that the blur takes the orientation of the shutter motion. It's subtle, and you clearly have the camera braced against vertical movement better than horizontal movement with the frame you have set up.

In portrait mode, The ball head is probably your weakest link. The single piece of metal that connects the ball to the mounting plate will allow a certain amount of twist to occur.

This will be difficult to specifically address, because we rely on gravity to help solve our vibration issues mostly.

The best way to easily address this (but not perfectly, to be sure) is probably mass. If you have the long lens support, you can mount it to the side down to a leg that is to one side (rather than directly below). That will give it some resistance to sideways movement, but won't necessarily make things better because the system may deflect slightly in another direction. May work well, though. You'll need to try it.

Lots of mass will dampen the movement considerably, regardless of the direction (an object at rest tends to stay at rest...).

However, to get the most out of the mass, it needs to be somewhat rigidly mounted as close to the camera as possible, because the issue is movement perpendicular to gravitational attraction. In other words, hanging a camera bag from the camera is great for vertical motion, but won't do much for horizontal motion.

I typically dampen a camera with my hand/arm with a little pressure to the body, clamped in my hand. That may be all that is required in this case. This approach won't be good for long exposures, but short ones, it may be sufficient.

One last thing, it takes A LOT more energy to move a camera/lens arrangement if the mass of the system is not centered over the pivot point. This has to do with the moment of inertia about that pivot point. This is why a skater will bring her arms and legs in to speed up in a spin, and then put her arms out to slow down to finish the spin. It is also why a piece of steel in an I-beam cross-section is much stronger/stiffer than the same amount in a solid rod.

So, having a load balanced on the tripod is good in many respects, but in this case, it reduces the value of the mass somewhat. That's why just a little mass or hand pressure at the camera may be all that is needed to effectively address this for short shutter speeds.


---Michael

EDIT: Let me revise this statement... The mass CAN be centered over the pivot point, but the majority of the mass needs to be away from the center of the pivot point to gain the most positive impact, and that is not what normally happens with cameras (which are like small weights that we center on the tripod).

Here's what I mean:

http://oregonstate.edu/instruct/exss323/Angular_Kinetics/barbell.htm

Even if the mass is centered, if most of the mass is farther out from the pivot point, it will be a more stable, less-prone to movement system.

 

[k-hawinkler]

Re: Shutter Shock at 784 mm in Portrait Mode!

Thanks again Michael, I agree.

 

[k-hawinkler]

Re: Shutter Shock at 784 mm in Portrait Mode!

Guided by the excellent feedback from several forum members - big thank you indeed - I decided to perform another experiment. Roughly 0.9 miles from my house is a telecommunications tower. I decided to take photos of that tower with the 784 mm rig shown in post #112 with Sony A7R, NEX-5N, and NEX-7, first in Portrait and then in Landscape mode. Timing in the late afternoon is a bit tricky. If one does this too early the tower still seems to be dancing because of the turbulent air heated by sunshine. If one waits until the turbulence has died down then it's already too dark for fast shutter speeds at base ISO. So, I tried to find a good compromise.

Here are the shots, all on Gitzo GT3541XLS tripod with RRS BH-55 ballhead and cropped to 1024x1024 pixels.
One is 1023x1023 as PS CS6 likes to play tricks on me!



Portrait mode, A7R + 784 mm tig, ISO 100, 1/160 s, wide open aperture, 10 s delay.
===> Shutter Shock sideways causes Double Image

Portrait mode, A7R + 784 mm tig, ISO 100, 1/200 s, wide open aperture, fire shutter by hand firm on camera, no delay.
===> Shutter Shock impact greatly reduced, no Double Image, still some blur

Landscape mode, A7R + 784 mm tig, ISO 100, 1/250 s, wide open aperture, 10 s delay.
===> Reasonably sharp image, a little affected by the 0.9 mile view through air with low levels of turbulence.

Portrait mode, NEX-5N + 784 mm tig, ISO 100, 1/200 s, wide open aperture, shutter remotely fired.
===> No visible Shutter Shock

Landscape mode, NEX-5N + 784 mm tig, ISO 100, 1/250 s, wide open aperture, shutter remotely fired.
===> No visible Shutter Shock

Portrait mode, NEX-7 + 784 mm tig, ISO 100, 1/160 s, wide open aperture, shutter remotely fired.
===> No visible Shutter Shock

Landscape mode, NEX-7 + 784 mm tig, ISO 100, 1/250 s, wide open aperture, shutter remotely fired.
===> No visible Shutter Shock

 

[k-hawinkler]

Re: Shutter Shock at 784 mm in Portrait Mode!

BTW, here is a shot up close of the same tower

with Olympus OM-D E-M1 + Olympus M.ZUIKO DIGITAL ED 75-300mm f/4.8-6.7 II Lens

 

[mjm6]

K-H,

Look carefully at the 5N and 7 images. There is some shutter shock visible in the portrait images.

Look at the diagonal bracing in the two segments below the location where they Guy wires connect to the frame. You can see a double image of the diagonal bars in the portrait images that is not there in the landscape version.

However, it is clear that the 5N and the 7 show less shutter impacts. It's no surprise, as the shutters are smaller, and do they also have electronic first shutter?

When I worked with ULF cameras (12x20 and bigger), I often used focal lengths in the 600-750mm range. I used a double tripod arrangement at times to keep everything tight. One at the lens end, and one at the film back end. Sure did suck to have to go to those measures.




---Michael

 

[k-hawinkler]

K-H,

Look carefully at the 5N and 7 images. There is some shutter shock visible in the portrait images.

Look at the diagonal bracing in the two segments below the location where they Guy wires connect to the frame. You can see a double image of the diagonal bars in the portrait images that is not there in the landscape version.

However, it is clear that the 5N and the 7 show less shutter impacts. It's no surprise, as the shutters are smaller, and do they also have electronic first shutter?

When I worked with ULF cameras (12x20 and bigger), I often used focal lengths in the 600-750mm range. I used a double tripod arrangement at times to keep everything tight. One at the lens end, and one at the film back end. Sure did suck to have to go to those measures.




---Michael

Thanks Michael.
You surely have better eyes than I do.
But now that you point this out it's consistent with what I see!
Thanks indeed!

 

[jonoslack]

Re: Shutter Shock at 784 mm in Portrait Mode!

BTW, here is a shot up close of the same tower

with Olympus OM-D E-M1 + Olympus M.ZUIKO DIGITAL ED 75-300mm f/4.8-6.7 II Lens

Hi there
How does it look with the E-M1 from the same distance? Interested to see.

 

[k-hawinkler]

Re: Shutter Shock at 784 mm in Portrait Mode!

Hi there
How does it look with the E-M1 from the same distance? Interested to see.

Hi Jono,

Thanks. Here you go, in Portrait mode, 100% crop, 1024x1024.

Olympus OM-D E-M1 + Olympus M.ZUIKO DIGITAL ED 75-300mm f/4.8-6.7 II Lens @ 300 mm, 135 film equivalent 600 mm.

 

[k-hawinkler]

Re: Shutter Shock at 784 mm in Portrait Mode!

Following philber's suggestion in post #316 of http://www.getdpi.com/forum/558394-post316.html I repeated the tests shown in post #125 of http://www.getdpi.com/forum/558028-post125.html by adding the battery grip.
Then my A7R + 784 mm lens looks like this.

After manual focus the tripod holds the camera and lens in a very stable position, even when the tower is viewed in extreme magnification of 14.4x through the EVF.
There is no doubt in my mind that I see a clear sharp image.

The following two images were taking with 10 s delay in portrait orientation and show a 100% crop of 1024x1024 pixels.


Portrait, ISO 160, 1/25 s

Portrait, ISO 1600, 1/200 s

From these two shots in portrait orientation, A7R with battery grip and 2 batteries in it I have to conclude the following:

At 1/25 s exposure time evidence of shutter shake is clearly visible.
At 1/200 s exposure time there is no evidence of shutter shake.


Now in post #125 of http://www.getdpi.com/forum/558028-post125.html I presented evidence that without the battery grip:

At 1/160 s exposure time evidence of shutter shake is clearly visible.


What now needs to be done are 2 series of shots in portrait mode, with and without battery grip, to cover the exposure range from 1 s to 1/200 s.
After these results are in we should have a better view of the issue at hand.

Of course, the same series should also be run in landscape mode.

According to Google Übersetzer this problem may have been with us mostly unnoticed for some time.
Thanks to member Gio for pointing this out. Thank you very much indeed!

Another interesting question for me is how the IBIS of the OM-D E-M1 behaves with such long lenses and exposure times?
Is it capable of extending the useable limits as indicated by Fritz Pölking's paper from or before 2000 Google Übersetzer ?

 

[k-hawinkler]

A7R + VARIO-R 105-280/4.2

 

[Guy Mancuso]

That looks nice and sharp

 

[algrove]

]

A7R + VARIO-R 105-280/4.2

K-H
The snow on that roof to the right side looks very sharp. Is this with the two extenders also?

 

[k-hawinkler]

That looks nice and sharp

Thanks Guy. Here is a 100% crop. BTW shot at Exposure Time: 1.6.

 

[k-hawinkler]

K-H
The snow on that roof to the right side looks very sharp. Is this with the two extenders also?

Lou,

Thanks. This was shot with just the lens, no extenders!
I really don't like to use extenders.
For extra reach I would typically use my NEX-7 with just the lens.
An FF camera would need to have about 57 MP to match the NEX-7's resolution of 24 MP.

 

[k-hawinkler]

Tale of two forest fires,
foreground Cerro Grande Fire - Wikipedia, the free encyclopedia in 2000
background Las Conchas Fire - Wikipedia, the free encyclopedia in 2011

50% crop

Sony A7R + Leica APO-R 280/4

 

[k-hawinkler]

Truchas Peak at 12.5%, Pano of 2 shots

Crop at 25%

Sony A7R + Leica APO-R 280/4

 

[k-hawinkler]

So, rather than trying to do too many things at once, I stepped back and took another look at getting a stable and vibration resistant landscape setup. What I wanted to do was couple the weight of the lens, rail, and tripod directly to the A7R. Here is my contraption with an APO-Extender-R 2x between the Vario 105-280 lens and adapter, resulting in a focal length from 210 to 560 mm.

There is now a plate attached to the camera that in turn is tightly attached to the rail.
The rail is also attached to the lens above the ball head.
Importantly the rail is also firmly attached via the ball head to the tripod.
What I also like is that I now need fewer parts!

I then ran a number of tests, according to this table.

The system seemed to behave in a very stable way.
All the results looked similar to this shot, taken at 1/50 s.:

Very encouraging.
I then went back to the APO-R 280/4 and extended it to a focal length of 1120 mm.
Here it is.

Well, how does that system behave on my tripod? I would say real well.

Here are some shots of a motive on a teapot.

ISO 100, 4 s

ISO 1000, 0.4 s

ISO 6400, 1/15 s

ISO 25600, 1/60 s

I haven't noticed any evidence of shutter shake. Do you see any? Thanks.

 

[Ron Pfister]

I haven't noticed any evidence of shutter shake. Do you see any?

Many thanks for doing these tests, Karl-Heinz! I had a feeling a setup of this kind would calm things down significantly, and it looks like it does. It's hard to judge finest detail in the high-ISO images, but the results are very encouraging. I would be interested to see what shutter speeds suitable for wildlife (i.e. in the range from 1/100s to 1/800s) at relatively low ISO would look like...

Edit: are the teapot images 100% crops?