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E-M1, E-M5, E-M5.2, etc. ... Peculiarities

scott kirkpatrick

Well-known member
Say, K-H, what will be happening at Bosque del Apache in late June? I have some business then in Socorro that leaves a few hours free.

scott
 

k-hawinkler

Well-known member
Say, K-H, what will be happening at Bosque del Apache in late June? I have some business then in Socorro that leaves a few hours free.

scott

Well Scott, there will be some local wildlife like this
https://whitenikonimages.smugmug.com/Other-3/Bosque-del-Apache-2017/
captured by a friend of mine in early March.

The snow geese and sandhill cranes will be returning in October/November.

Are you visiting Socorro proper or the relatively nearby VLA site?
If the former, the latter with its many radio telescopes is certainly worth a photography visit. Good luck. :)
 

scott kirkpatrick

Well-known member
....

Are you visiting Socorro proper or the relatively nearby VLA site?
If the former, the latter with its many radio telescopes is certainly worth a photography visit. Good luck. :)
Both, if time permits. But I have taken pictures at the VLA and ALMA sites in the past: aui_in_chile_2008 Photo Gallery by scott kirkpatrick at pbase.com ,
aui_in_chile_2011 Photo Gallery by scott kirkpatrick at pbase.com , radio_astronomy Photo Gallery by scott kirkpatrick at pbase.com , and especially
https://www.flickr.com/photos/133969392@N05/albums/72157664133999216 (ALMA, now in full operation).

BTW, the pictures of deer, turkeys, and hawks at Bosque del Apache suggest that not all the action there is migratory.

scott
 
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k-hawinkler

Well-known member
Here are 3 shots with my Olympus big tuna 300/2.8 SHG FT lens - that I bought used - with an AutoFocusMicroAdjustment in the E-M1.2 of AFMA = -3.


f/2.8


f/3.2


f/4.0


E-M1.2 + 300/2.8.


In the feathers of the front bird in the last image a moiré pattern is visible, indicating a sharp lens with feathers in focus.
Using f/3.2 seems a good compromise to keep ISO low and shutter speed high to counter subject motion.
 

Knorp

Well-known member
Here are 3 shots with my Olympus big tuna 300/2.8 SHG FT lens - that I bought used - with an AutoFocusMicroAdjustment in the E-M1.2 of AFMA = -3.

In the feathers of the front bird in the last image a moiré pattern is visible, indicating a sharp lens with feathers in focus.
Using f/3.2 seems a good compromise to keep ISO low and shutter speed high to counter subject motion.
Thanks for that info about the 'AFMA', K-H.
At what distance did you came to the -3 adjustment ?

TIA

PS the birds look a bit disappointed: isn't the bowl empty ?

Best regards.
 

k-hawinkler

Well-known member
Thanks Bart.

Thanks for that info about the 'AFMA', K-H.
At what distance did you came to the -3 adjustment ?

TIA
I get the same answer for 5, 6, 8, or 11m. Easiest to use is 5 or 6 m.
For 11m and 14x magnification it's pretty hard to focus precisely with a tripod, regardless the head one uses.
I use C-AF and 14x magnification when focusing and exposing to minimize the size of the focus box and attempt to place it precisely.
That's important when shooting a sloped target sheet. :facesmack:

Best focus for my lens is for an AFMA between -3 and -4.
So -3 seems a tad better than -4 for my lens.
If I don't correct I have to stop down to f/5.6 to get the focus point into the DOF. :banghead:

PS the birds look a bit disappointed: isn't the bowl empty ?

Best regards.
Yup, you are correct. Not completely empty though. But the birds have to reach way down.
After I took the images tonight we filled up a handful of water dishes to the rim! :thumbup:
We always put fresh water in first thing in the morning.
But now that the weather is warmer the water doesn't last all day.
Also all kinds of birds use the water dishes to take a bath. :LOL:
 

Knorp

Well-known member
Just tested and adjusted both my 300/4 (-3) and 150/2 (-8) on a tripod at approx. 6 mtr distance to the LensAlign FCS.
As we say in Holland: "meten is weten"...

Kind regards.
 

Knorp

Well-known member
Forgot to say that I'd noticed my lenses ever so slightly back-focused.
Now they're just slightly ahead, let's see how that turns out in practice.

Krgds
 

k-hawinkler

Well-known member
Thanks Bart.
You can always pull back the AFMA a smidge so that your lens is spot on.
Test wide open. Then stop down 1 f-stop for sharpest image. Good luck! :thumbs:
Final test on a real subject. If that nails it then one is done.

:worthless:

I had the feeling my other tele lenses were spot on.
But I should test them as well to be sure. :grin:

My four FT lenses 50-200/2.8-3.5 SWD, 90-250/2.8, 150/2.0 and 300/2.8 each now has its own original Olympus FT to MFT adapter that stays with that lens. :loco: :grin:

Following Roger Cicala of lensrentals fame
https://www.lensrentals.com/blog/2017/03/rogers-law-of-wide-zoom-relativity/
zoom lenses should be particularly interesting.
 
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k-hawinkler

Well-known member
As the E-M1.1 or E-M1.2 doesn't have a separate AF sensor, obviously misalignment cannot be the reason for Olympus to provide for "Focal location adjustment for phase-difference AF" that "can be fine tuned within a range of ±20 steps.", quoting from page 112 of the "E-M1 Mark II Instruction Manual". So we have to look for another explanation. This thread
https://www.dpreview.com/forums/thread/3546169#forum-post-52156580
offers some intriguing points, namely, quote:


• "While you are right that in the case of the E-M1 that the camera should not give rise to any back/front focus error the lens can also be a source of error.


The PDAF sensor system determines the amount and the direction that the lens needs to move and then tells it to go there. Once the lens has made its focus change the PDAF system then makes another assessment and if the result is within tolerance the focus is considered set. With fast aperture lenses the tolerance allowed by the focus system can result in a small focus error that would not be seen using a slower lens being masked by the greater DOF.


Olympus could reduce the tolerance now that the camera is no longer a source of error but that would result in the focus system taking a second stab at achieving focus. The result would be slower and more jittery focusing with such lenses. Fine tuning allow for any lens errors to be compensated for so that the PDAF can achieve accurate focus at the first attempt most of the time."


• "Focus adjust does work with m4/3 lenses, but only in c-af mode where the PDAF system is being used. Focus adjust has no effect on m4/3 lenses in s-af."


The E-M1.2 also features in "Menu/A1" an "AF Scanner" that in my camera is set to mode2. Page 111 of the manual explains:


"Sets the AF scan function* for when the camera cannot
focus on the subject or the contrast is not clear.
* Scans whole range from minimum range to infinity for
focus point when the camera cannot focus on the subject
or the contrast is not clear.
[mode1]: AF Scanner is not activated.
[mode2]: AF Scanner is activated once only.
[mode3]: AF Scanner is activated."


I wonder what happens when mode3 is chosen. Dunno as I have not experimented with that option.
 

Knorp

Well-known member
• "Focus adjust does work with m4/3 lenses, but only in c-af mode where the PDAF system is being used. Focus adjust has no effect on m4/3 lenses in s-af."
Hi there K-H,

Without going into details now, it seems a bit of an odd statement. Have to check my 300/4 and 150/2 again with both S-AF en C-AF ... :facesmack:
Wonder what your findings are.

Kind regards.
 

k-hawinkler

Well-known member
Hi there K-H,
Without going into details now, it seems a bit of an odd statement. Have to check my 300/4 and 150/2 again with both S-AF en C-AF ... :facesmack:
Wonder what your findings are.

Kind regards.

Thanks Bart, Sorry, but the following is correct for my E-M1 Mark II: :facesmack:

• "Focus adjust does work with m4/3 lenses, but only in C-AF mode where the PDAF system is being used."
• "Focus adjust has no effect on m4/3 lenses in S-AF."

Very easy to verify with E-M1.2 and mFT 300/4.0 PRO.
Set AFMA=-10 or +10, shoot with C-AF image OOF, shoot with S-AF image in focus, same as with AFMA=0. :grin:
BTW shoot AFMA=0 with both S-AF and C-AF gives in focus images and an easy way to see how Olympus defines in focus. :thumbup:

I find this reassuring as Sony's native FE lenses cannot be AFMAed but their adapted A-mount lenses can IIRC.

One more thing, switching IBIS off greatly aids precise focusing under 14x magnification. If IBIS is on focus point floats.

For my FT 300/2.8 SHG lens both C-AF and S-AF are affected by the AFMA setting.
 
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k-hawinkler

Well-known member
So I went through the relatively time consuming process of AutoFocusMicroAdjustment (AFMA) for my four Olympus FT lenses on my E-M1.2. Here are the AFMA corrections I settled on for now by shooting markings on an oblique plane. I used Tim Jackson's autofocus test chart.
http://www.kscameraclub.org/docs/pdfs/focus_test_chart_edited.pdf


• HG . 50-200/2.8-3.5 SWD: AFMA = -2
• SHG 90-250/2.8: @250m . AFMA = -3 z(oom) tuna <-- I just made that up! :loco: :grin: :LOL:
• SHG 150/2.0: ................. AFMA = -2 little tuna
• SHG 300/2.8: ................. AFMA = -3 big tuna


 

k-hawinkler

Well-known member
All your Tunas seem to be a little 'far sighted' ... :grin:
Thanks Bart. 'far sighted'? I like the ring of that, as looking into the future! :bugeyes: :LOL:
So let's look at images to get a better understanding of the effects we are talking about here.
As a baseline here is an image taken with the mFT 300/4.0 PRO and S-AF that cannot be adjusted, so according to Olympus is spot on focus.
I had the chart standing on its head (to get more light) when I took the image, so the upper part is far and the lower part is near.
Using C-AF with AFMA=0 gives the same result.



E-M1.2 + 300/4.0 @ f/4.
 

k-hawinkler

Well-known member
So Bart, could you please show the images how you ended up with AFMA=-3 for 300/4 PRO and AFMA=-8 for little tuna? TIA

Here are my charts for little tuna. AFMA=-1 is not enough correction :facesmack:, AFMA=-3 is too much :facesmack:, so AFMA=-2 is my best guess. :grin: :thumbup:

AFMA=0


AFMA=-2


E-M1.2 + 150/2.0 @ f/2.
 
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