New images taken (2nd time using my setup), need some help

Just bought that first macro lens? Post here to get helpful feedback and answers to any questions you might have.

Moderators: rjlittlefield, ChrisR, Chris S., Pau

leekekhuan
Posts: 74
Joined: Thu May 21, 2015 7:38 am
Location: Singapore

New images taken (2nd time using my setup), need some help

Post by leekekhuan »

Hi,

So i got my stackshot, and it is one of the great piece of hardware.

Took a few shot today
1-
Image
If i process all picture it give me weird shape on edge, any one got any idea what is this?
Image

2-
Image

Now here is how my setup look like.
Image

1- Flash in ETTL mode.
2- Camera in manual mode at 1/60.

I think flash is still bit harsh, will it be good idea to change flash to manual mode?
Pictures seems a bit blur, i am still waiting for arrival of Light trap tape roll from Protostar.

Any idea how i can improve it to get sharper image with more detail? When i look at 100% it is very blur.
BTW these pictures are straight out of camera except pic 1, just resized to meet the standard.

Pau
Site Admin
Posts: 6051
Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Post by Pau »

Hi leekekhuan,

At the studio and even more for stacking manual mode is more convenient, you will avoid illumination changes that usually happen in auto mode (and you'll save a bit of battery avoiding the preflash). You also can benefit of mirror lock up if your camera allows it.

The harsh illumination doesn't come from auto mode but from insufficient light diffusion: your diffuser seems big but not so much from the angle of view of the subjet. A diffuser surrounding the subjet -you've tons of examples at the forum- will be much more effective.

Your stacks look very promising :D

Note: Despite taken with microscope objectives, following our forum conventions they are more adequate for posting at a Macro than at a Microscope forum
Pau

leekekhuan
Posts: 74
Joined: Thu May 21, 2015 7:38 am
Location: Singapore

Post by leekekhuan »

Thank you Pau, in this case can you please assist to move this to macro section.
Will look for more diffuser posts.

rjlittlefield
Site Admin
Posts: 23561
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Re: New images taken (2nd time using my setup), need some he

Post by rjlittlefield »

leekekhuan wrote:If i process all picture it give me weird shape on edge, any one got any idea what is this?
Those are "Edge streaks". They usually indicate a problem with physical alignment of the setup. In some cases the issue can be created by the computational alignment process, when the computation gets misled by the way that parts of the subject go in and out of focus. But that usually happens when the composition is very asymmetric, for example with a bright subject overlapping one side of the frame and not the other. For this stack, I suspect the misalignment is physical.

For more discussion, see HERE in the Zerene Stacker FAQs.

--Rik

Charles Krebs
Posts: 5865
Joined: Tue Aug 01, 2006 8:02 pm
Location: Issaquah, WA USA
Contact:

Post by Charles Krebs »

Any idea how i can improve it to get sharper image with more detail? When i look at 100% it is very blur.
One thing that stands out is the bellows extension. (Although I can only make some guesses based on the picture you posted). It appears that you are using a Nikon M-Plan 10/0.25 210/0 objective (?). If this is the case there should be about 200mm total extension from the "seat" of the objective to the camera sensor (This will give a 10X magnification). Your Canon body is 44mm from mount surface to sensor. In the picture it appears that there may be about 310mm of extension from the base of the objective to the camera mount. So your overall extension is about 340-350mm (If I am interpreting the picture correctly). In doing this you will get a much higher magnification than the rated 10X, but you are also greatly reducing the "effective aperture" which causes more resolution loss from diffraction. There's no question that this drop in resolution would be noticeable, but whether or not that is the only reason for your dissatisfaction I can't say. With a 10/0.25 you can use a bit more than 200mm extension without serious ill-effects, but if you find yourself using nearly double the intended extension you should really look at at higher power objective. These will typically have a larger NA (a lower "effective aperture") so you will get a "sharper" image.

In addition to diffraction, vibration is another key problem when it comes to "sharpness". As Pau mentioned, with flash you are better off using the mirror lock-up feature of the camera with a pause after "mirror up" before taking the picture. You've got a lot of camera/bellows perched pretty high on two relatively narrow support sections, so even with electronic flash it would be recommended to set the controller to include an adequate pause time (after mirror up) to allow things to "settle". You should experiment a little with the pause time... probably something in the 1 second to 4 second range.

leekekhuan
Posts: 74
Joined: Thu May 21, 2015 7:38 am
Location: Singapore

Post by leekekhuan »

Thank you for your kind reply.
Charles, can you give me any example of objective. I am bit new to this objective arena and would appreciate if you can link me to objective to have better understand.
Thanks again for all of your time and passion in answering questions.

Charles Krebs
Posts: 5865
Joined: Tue Aug 01, 2006 8:02 pm
Location: Issaquah, WA USA
Contact:

Post by Charles Krebs »

For starters read through this post:
http://www.photomacrography.net/forum/v ... hp?t=17073

Then look here:
https://www.microscopyu.com/articles/op ... specs.html

Look at the markings on your objective. If it is the one I suspect, you will see:

Nikon M Plan: This is the series or type of objective. the "M" typically designates metallurgical (or metallographic)... an objective primarily designed to be used with no cover glass and usually with reflected light and opaque subjects.

10 and 0.25: The magnification (when properly used) is 10X. The numerical aperture (NA) is 0.25. The numerical aperture is a measure of the light gathering ability of the objective, and can be thought of as analogous to the largest aperture, (numerically smallest f-number), on a photographic lens. The higher an objectives NA, the higher the resolution it can provide (but typically... not always... the higher the NA the shorter the working distance).

210/0: This would indicate a "finite" type objective with a mechanical tube-length of 210mm. The "0" indicates that it is intended to be used with no glass coverslip over the subject.

Not indicated on this objective is the working distance which is 9mm.
see: http://www.krebsmicro.com/mplan.pdf


With a finite objective, the image is formed at a distance of 10mm less than the stated tube length. (So in this case, the image is formed at a distance of 200mm from the back shoulder seat of the objective.) If you are to use the objective on a bellows or with tubes, that is the distance you want between the camera sensor and the objective. If you use a smaller extension you will get a smaller magnification (and a smaller overall image that may not cover a large camera sensor). If you use a larger extension you will get a larger magnification. However, you do not increase the NA, so as a result there is a greater diffraction effect and resolution will suffer. (That's why, if you are always greatly extending over 200mm you might be better off getting a 20X objective. These typically have an NA of about 0.40. The working distance will be smaller but the resolution will be much higher. (For example, in the same series of objectives as the one you have there is a a Nikon M Plan 210/0 LWD 20/0.40 that has a 6mm working distance).

Also, if you vary the extension greatly from the design point, you can introduce optical aberrations. This is generally not much of a concern with numerical apertures belowabout 0.30, but gets to be a bigger problem as the NA increases.

Post Reply Previous topicNext topic