Problem/Disturbance at 10x using Wemacro Rail/200mm f4 lens

[Saul]

...A good thing to do is to set up on a subject and focus so that you can see some very small specular highlights. Magnify those on the rear LCD screen as much as the camera allows. Observe the specular highlight and see if it "jiggles" at all (it should nor during the actual exposure). Gently "tap" the camera or lens and see how long it takes for the system to settle down. ...

...and I'm also using Sensor Kinetics Pro app from http://www.rotoview.com/sensor_kinetics.htm , it helps to "catch" some vibrations

[skrama]

. With auto ISO, at Ts=1/100, f=4, the ISO obtained by a7R ii was 2000, so I fixed the ISO at 2000. I turned on the Silent Shutter option on a7R ii.

I don't understand why you would want to use ISO 2000 with a subject like this. If you are at 1/100 sec at ISO 2000, then you would be somewhere around 1/4 second at ISO 100. Even with an excellent camera like the a7R II your image quality would be better at ISO 100-200. And importantly, noise "build-up" in PMax stacking mode should be far less.

The f-stop setting on the lens really doesn't do much of anything as long as it is large enough to avoid vignetting. With a fully electronic shutter, a shutter speed of 1/4 second is perfectly fine... as long as there is no external ("environmental") source of vibration. (And if that were the case you should be using high speed flash for your lighting).

A good thing to do is to set up on a subject and focus so that you can see some very small specular highlights. Magnify those on the rear LCD screen as much as the camera allows. Observe the specular highlight and see if it "jiggles" at all (it should not during the actual exposure). Gently "tap" the camera or lens and see how long it takes for the system to settle down. While the electronic shutter should not cause any vibration problems, the mechanical movement of the rail as it steps to the next position could. You want to be sure you set sufficient "settle" time on your stacking controller. Be aware of anything that might cause "environmental" vibrations... walking around, moderate to loud music, fans, air conditioners. Even an operating clothes washer or dryer in another part of a frame house can sometimes be an issue.


On that first image...

The flower wasn't wilting as it was a fresh flower from the plant.

Did you carefully check the source images as Rik suggested? "Wilting" or slight changes in shape of plant matter is a very significant issue for large stacks. Even when I take special care (as Beatsy suggested) it still occurs during a significant number of large stacks. It may be barely noticeable unless you check for it.

Rik et al you are right. Even though the flower was freshly plucked from the plant, when I "play" the trajectory of the frames, there is some slight jump in the "amount of the area covered by stamens" and is changing.

Also, even after cleaning the sensor after the very first experiment (which started the whole thread), I do see a small speck of dusk on my sensor towards lower middle (pointed with arrow) in the image attached. This is the image of 1 cent since that won't move like those stamens. I will try to clean the sensor again or send it to Sony to get it cleaned.

Many thanks for all the suggestions.

[skrama]

...A good thing to do is to set up on a subject and focus so that you can see some very small specular highlights. Magnify those on the rear LCD screen as much as the camera allows. Observe the specular highlight and see if it "jiggles" at all (it should nor during the actual exposure). Gently "tap" the camera or lens and see how long it takes for the system to settle down. ...

...and I'm also using Sensor Kinetics Pro app from http://www.rotoview.com/sensor_kinetics.htm , it helps to "catch" some vibrations

Which sensor do you check for the vibrations? Do you keep the phone on the table or on the rail?

I tried to put the phone on the camera and didn't see any unusual vibrations that were there when the phone wasn't on the camera. But I would like to know how set this up for "catching vibrations".

Thanks!

[Saul]

...Which sensor do you check for the vibrations? Do you keep the phone on the table or on the rail? ...

Linear acceleration or Accelerometer. I kept on the different things - camera, rig extrusions, rig base, table, floor - trying (like Charles mentioned) what, when and where vibrations are coming from. So now, during the stacking, my rig sits on the floor carpet, no washing machine is on, dog is locked in the laundry room, family is not at home, HiFi is off (at least sub-woofer), window in the room is closed, flash is not too close to the object, I'm in the different room with 2Brother IPA beer ...

If you bought Pro version, try different filter settings, that helps.
I have a plan (tested simpler version) to make special "sandwich" pad, made from plywood and anti-vibration rubber between column head and microscope nose piece to absorb more shutter vibrations and transfer less to the rig.
http://www.photomacrography.net/forum/v ... 007#208007

[JH]

I will try to clean the sensor again or send it to Sony to get it cleaned.

The sensor is almost never totally clean when photographing at high magnification/large f-number.

Try a blower with a filter - a blower witout a filter usually adds some more dust spots.

Be prepared to do some dust-removal in Lightroom or some other program before stacking.

Best regards
Jörgen Hellberg