A7r4 pixel shift. Rather a resolution eye-opener

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Lou Jost
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by Lou Jost »

Well, it's nice to hear that these new imaging technologies have still not made that Vivitar obsolete. Probably the cheapest lens in your kit? Very impressive.

Duke
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by Duke »

I wonder, why options only are FF(36x24) or APS-C-mode(24x16)...
Wouldn't it be better to use square crop (24x24mm), from the FF picture, so no field is wasted?
“Thoroughly conscious ignorance is the prelude to every real advance in science.” - JCM

Beatsy
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by Beatsy »

Duke wrote:
Fri Apr 09, 2021 7:02 am
I wonder, why options only are FF(36x24) or APS-C-mode(24x16)...
Wouldn't it be better to use square crop (24x24mm), from the FF picture, so no field is wasted?
You're quite correct, it would be, but I had to allow for system/kit limitations too...

Full-frame 16-shot pixel shift is far too "heavy" for the general case such as shooting insects which need much deeper stacks than this chip did. The 16 x 61 megapixel, full frame, uncompressed RAW shots are 122Mb each - or nearly 2Gb per frame. I don't (currently) have memory cards with enough capacity to shoot a moderately deep FF stack at that rate (even with auto spill over to a second card). Changing a card would risk moving something mid-stack and tethering is way too slow (as things are set up now). So I optimised for APS-C because it works best in the general case when I'm using Mitties on this rig (which I was here).

Having said that, I often do exactly as you suggest when I have the camera on my main microscope (most recently with 4-shot shift for colour resolution). But still only for single shots or shallow stacks (20-30 pics or less).

AshAsh
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by AshAsh »

Beatsy wrote:
Thu Apr 08, 2021 11:13 am
Lou Jost wrote:
Thu Apr 08, 2021 7:54 am
Hi Beatsy, which 135mm lens did you use for this test? I remember you had a fancy 135mm (Samyang/Rokinon? or Zeiss?) which you rejected because of vignetting. In crop mode that wouldn't be a problem. I like my cheap Vivitar-Komine 135mm but my Sigma Art 135mm gives better results, apart from hard vignetting in the extreme corners on FF.
Same Vivitar/Komine as you have - from your recommendation many years ago.

Yes, I still have that Samyang - languishing somewhere. I bent a stacking rail with it too (weight + imbalanced). I've replaced it for normal togging with a 135/1.8 G-Master. Now *that* is a proper 135mm lens. It vignettes as a tube lens (yes, it had to be tried) but it's way too good for "normal use" to be used as a tube lens anyway. The Vivitar works very well as it is, no need to change...

Cheers
Hi Beasty
Please forgive me if this is too off topic, it’s my first post ever on the forum. I recently bought a mitutoyo 5x & 20x and I’ve been trying to research what to use as a tube lens on my a7iii. I own a sony 100-400GM and a sony 135GM and I seem to have a fairly noticeable vignette on the 100-400 @200mm, @400mm it’s better but still there in the extreme corners. I just ordered a 82-77 step down ring so I can try mounting it on the 135. I have 2 questions, 1) can I always expect massive vignette when shooting ff or are some tube lenses better at filling the frame if so which have you had the best luck with on your Sony? 2) when you mount it on the 135, I believe you called it “pushing it down”, does that improve the image quality and/or depth of field or do you do that simply to get a different desired magnification?

Beatsy
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by Beatsy »

AshAsh wrote:
Thu Jul 15, 2021 7:18 pm
Beatsy wrote:
Thu Apr 08, 2021 11:13 am
Lou Jost wrote:
Thu Apr 08, 2021 7:54 am
Hi Beatsy, which 135mm lens did you use for this test? I remember you had a fancy 135mm (Samyang/Rokinon? or Zeiss?) which you rejected because of vignetting. In crop mode that wouldn't be a problem. I like my cheap Vivitar-Komine 135mm but my Sigma Art 135mm gives better results, apart from hard vignetting in the extreme corners on FF.
Same Vivitar/Komine as you have - from your recommendation many years ago.

Yes, I still have that Samyang - languishing somewhere. I bent a stacking rail with it too (weight + imbalanced). I've replaced it for normal togging with a 135/1.8 G-Master. Now *that* is a proper 135mm lens. It vignettes as a tube lens (yes, it had to be tried) but it's way too good for "normal use" to be used as a tube lens anyway. The Vivitar works very well as it is, no need to change...

Cheers
Hi Beasty
Please forgive me if this is too off topic, it’s my first post ever on the forum. I recently bought a mitutoyo 5x & 20x and I’ve been trying to research what to use as a tube lens on my a7iii. I own a sony 100-400GM and a sony 135GM and I seem to have a fairly noticeable vignette on the 100-400 @200mm, @400mm it’s better but still there in the extreme corners. I just ordered a 82-77 step down ring so I can try mounting it on the 135. I have 2 questions, 1) can I always expect massive vignette when shooting ff or are some tube lenses better at filling the frame if so which have you had the best luck with on your Sony? 2) when you mount it on the 135, I believe you called it “pushing it down”, does that improve the image quality and/or depth of field or do you do that simply to get a different desired magnification?
Hi, and welcome to the forum.

There's a little bit about tube-lenses in the FAQs - e.g. viewtopic.php?f=29&t=20061 - and there may be more.

Mitties, and most other "infinity corrected" objectives require a 200mm tube-lens to give their rated magnification on the sensor. When you use a shorter focal length, you "push down" the magnification proportionally, so a 135mm tube lens will turn a 20x objective into 20x * 135 / 200 = 13.5x magnification. The image circle that you can cover on sensor will shrink proportionally too. As Mitties barely cover FF at 200mm (with mushy corners), they only cover an APS-C crop area when pushed down. Less if you push down more. Image quality improves in the sense that you are making fine details smaller, so if you were at diffraction limits with 200mm, you might push the image down past them at 135mm to make it look sharper (but smaller). Note: the distance between frames in the stack may need to be smaller with a pushed-down objective too - so you may have to shoot more frames per given depth of field (unless the image was very soft from diffraction at 200mm in which case the same focus spacing will work fine to sharpen that up)

Modern lenses tend to vignette a lot - as you have found. Best "luck" seems to be with older M42 primes. The Vivitar/Komine 135mm (with red "MC" in the name) is one of the stand-outs performance-wise (no vignette and sharp). People also use Raynox DCR250 or DCR150 lenses as tube lenses (those are mentioned in the faq too). Primes aren't designed with use as tube lenses in mind, so there's always an element of "try it and see" in this area.

Hope that helps. just ask if you have more Qs

cheers

AshAsh
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by AshAsh »

Beasty,
Thanks for the info and pointer to more info :D
Best,
Ash

ray_parkhurst
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by ray_parkhurst »

How do you trigger the shutter release on the A7Rm4?

Beatsy
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by Beatsy »

ray_parkhurst wrote:
Mon Jul 19, 2021 5:47 pm
How do you trigger the shutter release on the A7Rm4?
The WeMacro rail controller fires it - either wired, or via IR remote.

ray_parkhurst
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by ray_parkhurst »

Beatsy wrote:
Mon Jul 19, 2021 11:17 pm
ray_parkhurst wrote:
Mon Jul 19, 2021 5:47 pm
How do you trigger the shutter release on the A7Rm4?
The WeMacro rail controller fires it - either wired, or via IR remote.
It has both Micro-USB and USB-C. Which one does the triggering?

Reason I ask is that I'm finally getting one (again) and want to make sure I have the right cable, and that it's going to work with wired USB triggering.

Beatsy
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by Beatsy »

Must be micro usb as there's no USB-C on A7rii, the first body I used it with. Not there to look, sorry. The IR remote method is better IMO as it leaves the usb port free for power and tethering.

ray_parkhurst
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by ray_parkhurst »

Beatsy wrote:
Tue Jul 20, 2021 4:55 am
Must be micro usb as there's no USB-C on A7rii, the first body I used it with. Not there to look, sorry. The IR remote method is better IMO as it leaves the usb port free for power and tethering.
I'm using an older mjkzz controller with hardwired triggering, so am hoping the second USB is set up for triggering.

ray_parkhurst
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by ray_parkhurst »

Well, my A7Rm4 arrived and I am shooting with it. My intent was to improve the workflow for my high resolution images of Lincoln Cent varieties. With my HRT2i, I must stitch a 2x3 panorama to end up with a ~9400x9400 final image. Each tile is done at ~2x with the 95mm Printing-Nikkor, shooting in RAW, stacking and stitching in TIF, and final output in JPG. With the A7Rm4, I can do a 1x2 panorama, with each tile shot at ~1.8x with the 95PN. My first attempt was done shooting/stacking/stitching/final output in JPG, and it came out about equal quality IMO to much more complex HRT2i workflow.

Turns out triggering is done on the micro-USB input, while tethering is on the USB-C. Works great using Sony's Imaging Edge Remote app.

I did try stack and stitch using pixel-shift, but the workflow was onerous. Even with just the 1x2 panorama, I never made it through to the end. Either my computer needs upgrading, or the software simply sucks, but either way I will need to find another way to do it. Meantime I am able to simplify the workflow quite a bit as it is much, much easier to shoot and tile a 1x2 vs a 2x3 panorama, and I'm not seeing the oversharpening problem when shooting in JPG mode. I am anxious to see the improved IQ from a Raw/Tif workflow like I did with the HRT2i soon as I can figure out an acceptable workflow.

So, it looks like I will be keeping the A7Rm4 this time. I can see a lot of new lens tests in my future to see which of my lenses are FF capable. Will be interesting!

If you want to see the comparison between HRT2i and A7Rm4 in the mode describe above, see them at links below. The images are of the same variety, but not the exact same coin, so the compo is not perfect, but still gives a good impression.

HRT2i in RAW-TIF
https://easyzoom.com/image/124047/album/0/4?mode=manage

A7Rm4 in JPG
https://easyzoom.com/image/277499/album/0/4?mode=manage

rjlittlefield
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by rjlittlefield »

I get a "404 page not found" error on the second one.

--Rik

ray_parkhurst
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by ray_parkhurst »

rjlittlefield wrote:
Wed Jul 28, 2021 10:23 pm
I get a "404 page not found" error on the second one.

--Rik
Hmm, it goes to the page for me.

Pau
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Re: A7r4 pixel shift. Rather a resolution eye-opener

Post by Pau »

rjlittlefield wrote:
Wed Jul 28, 2021 10:23 pm
I get a "404 page not found" error on the second one.
I get the same, check if it is password protected
Pau

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