Live-View, Legacy Lenses ... and CoC!

[xpatUSA]

I'm almost always in manual, but my diabetic's eyes are slowly deteriorating. I'm having great difficulty focusing legacy lenses on a DSLR. So I'm considering getting a mirror-less ILC. In a discussion elsewhere about the merits of live-view magnified manual focusing versus range-finders, someone pointed out that the image plane has a CoC and therefore a range of 'acceptably sharp' focus based on pixel size.

Now, with many legacy lenses from the film era, everything is manual which appeals to this old man. But if I set my 24mm Takumar to f/8 then there would be a bigger CoC than wide open. From a sensor point of view, that CoC is perhaps based more on sensor pixel pitch than on the hypothetical 8x10" print held a foot from one's nose.

What I find, even with focusing on a target with the DSLR's optical viewfinder and even with a 1.34X magnifier, the point of 'perfect' focus is impossible to find with any confidence - it's all too 'mushy'. My question (finally) is "if I get a mirror-less to use with legacy lenses, will it focus significantly better?".

On the camera I would buy, the conventional 1/1500 CoC is 0.019mm. On the other hand, the pixel pitch is 4.32um, although I would probably shoot in low-res binned on-chip, effectively 8.64um.

[JBW]

thinking a little out of the box: would either a dental or a surgeons loupe be of any use?

[george013]

I'm almost always in manual, but my diabetic's eyes are slowly deteriorating. I'm having great difficulty focusing legacy lenses on a DSLR. So I'm considering getting a mirror-less ILC. In a discussion elsewhere about the merits of live-view magnified manual focusing versus range-finders, someone pointed out that the image plane has a CoC and therefore a range of 'acceptably sharp' focus based on pixel size.

Now, with many legacy lenses from the film era, everything is manual which appeals to this old man. But if I set my 24mm Takumar to f/8 then there would be a bigger CoC than wide open. From a sensor point of view, that CoC is perhaps based more on sensor pixel pitch than on the hypothetical 8x10" print held a foot from one's nose.

What I find, even with focusing on a target with the DSLR's optical viewfinder and even with a 1.34X magnifier, the point of 'perfect' focus is impossible to find with any confidence - it's all too 'mushy'. My question (finally) is "if I get a mirror-less to use with legacy lenses, will it focus significantly better?".

On the camera I would buy, the conventional 1/1500 CoC is 0.019mm. On the other hand, the pixel pitch is 4.32um, although I would probably shoot in low-res binned on-chip, effectively 8.64um.

A coc sec doesn't exist, so nothing to border about. As we use it, it's the max diameter of the top of the topped off light cone diaphragm-sensor. It's nothing else as the max value of that based on a print that's viewed at a certain distance at a certain print size.
On my old camera I installed a Katz Eye, an old fashioned focusing screen. But they don't exist anymore.

George

[DanK]

Wouldn't focus peaking address this problem? I have no idea, however, whether focus peaking works with legacy lenses.

[Manfred M]

In my view the "best" way of confirming focus is to shoot tethered. Is that something you can do with your camera?

Viewing the image sharpness on a large screen (when compared to the small screen on the back of a camera) is the best way to go. Shooting tethered is the preferred method of confirming focus in high end commercial work. A similar method is used when shooting feature films.

[Manfred M]

Wouldn't focus peaking address this problem? I have no idea, however, whether focus peaking works with legacy lenses.

I find that focus peaking sort of works, especially if one is not too fussy on nailing the exact focus point. It is little more than a way of visualizing what the contrast detect autofocus does. Again, small screen = somewhat limited usability.

On my Panasonic GX7, I can confirm that once I set the camera to manual focus mode, focus peaking works for my old manual lenses that I have fitted with an adaptor.

[rpcrowe]

Apparently (I say apparently because I have used only the A6500) there are some great differences in the quality (therefore the ease of focusing) of the LCD and eye level viewfinders between various brand mirrorless cameras and even between different models of the same brand.

I combine both Focus Assist (magnifying the live view) and Focus Peaking when I shoot with legacy lenses on my mirrorless A6500 and have no problems achieving focus. However, I tend to choose native auto focus lenses for my Canon and Sony cameras when I want to capture moving subjects.

Here are a couple of tips which may or may not help when using Focus peaking. I don't know if these features are available on all cameras but, they help when manually focusing lenses on my A6500.

1. Color of the focus peaking: You have the choice of red, yellow or white focus peaking. When shooting a subject that is predominantly one color, it helps to use a different color for the Focus Peaking. As an example, when shooting red Bougainvillea, I would not use red as my Focus Peaking color...

2. Degree of focus peaking: You can choose between high, medium or low focus peaking. Sometimes it is easier to have a high degree of focus peaking while at times it is easier to lower the amount of peaking shown in the viewfinder. That all depends on your subject. I find it easier to use a low level in portraits because I can easily see the focus on the eyes...

3. Setting the camera to take black and white images will result in a black and white image being shown in the viewfinder and the colored focus peaking will be very apparent. If you have your camera set to record JPEG and RAW, the RAW images will be in color.

4. Double tapping the area you need to be in sharpest focus with the A6500 will enlarge that portion of the image.

There are different qualities of viewfinders among the various cameras out there. As an example, the Sony A7iii is said to have a sharper and better quality viewfinder than my A6500 (although the little A6500 does a pretty decent job).

I ALWAYS have better luck using an eye level viewfinder than trying to focus using the LCD screen!

FINALLY: I have the devil's own time viewing with the LCD in bright sunlight. I solved this problem with my 6D Mark-2 by adding a SwiVi viewfinder.
https://www.youtube.com/watch?v=prycBf9eBpU
This viewfinder, combined with LiveView of the 6D2 gives me the clearest and brightest picture that I have ever used with any camera. Since the dual pixel auto focus of the 6D2 is really excellent and can lock on to the subjects eyes when using face detect; the SwiVi + 6D2 combination is an excellent way for those of us with senior eyesight to focus and view our images. Unfortunately, it is rather large and is not the most handy way to use this camera for fast moving events.

[xpatUSA]

thinking a little out of the box: would either a dental or a surgeons loupe be of any use?

I do have a jeweler's loupe, 2 different diopters, no headband though.

I could try it at low magnification in place of the 1.34X magnifier, I suppose. But my original question remains "if I get a mirror-less to use with legacy lenses, will it focus significantly better?".

Hoping to get an answer to that rather than advice how to fix my poor focusing with legacy lenses on my non-live-view DSLR.

[rpcrowe]

Ted...

In answer to your stated question, I would say that in my experience, manual focusing is far easier and more accurate using my Sony A6500 than using either my Canon 7D Mark-2 or my 6D Mark-2 especially using the eye level viewfinders of these cameras and I never liked using manual focus lenses with my Canon DSLR cameras that did not have LiveView...

However, as I mentioned in my last post I primarily use my Legacy lenses on static subjects or portraits and leave the fast moving subjects to my native AF lenses. I absolutely love my native Sony glass for its continuous Eye AF capability. I especially like the Sony 85mm f/1.8 lens with its Focus Lock Button that I have reconfigured to Eye AF. But, the A6500 (and probably most of the other later issue Sony mirrorless cameras) does a very nice job catching focus on the eye on manual focus mode even with manual focus lenses. OTOH, it is certainly not as fast and as easy as using a camera/lens with Continuous Eye AF, especially if you or your subject are moving...

That is not to say that we can't use manual focus on moving subjects - we have had manual focus lenses a far longer time that we have had auto focus lenses and could definitely work around the manual focus...

However, due to the differences in viewfinder quality between cameras, I would guess that the ease and accuracy of focusing might vary considerably depending on which mirrorless camera you choose...

I presently own four manual focus lenses. Two are Legacy glass: 135mm CZ Triopar f/3.5 and Auto Sears (Tomioka produced) 55mm f/1.4; plus, I have two modern lenses which are manual focus: 12mm f/2 Rokinon and an 80mm f/1.7 Night Owl security camera lens (adapted to the Sony e mount)... I will also use some of my Canon glass on the A6500 with a MC-11 adapter. I can auto focus some of these lenses but with others, like my Canon 100mm f/2.8 Macro; it is easier to manually focus.

[pschlute]

Cannot advise on the mirrorless, but when i want to absolutely nail focus on a DSLR, the camera is on a tripod and I use Live View zoomed to 100% view. never fails.

[xpatUSA]

In my view the "best" way of confirming focus is to shoot tethered. Is that something you can do with your camera?

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Not possible with my existing DSLRs. However, the recent Sigma mirror-less sd Quattro ILC can be tethered, provided one carries a laptop with Sigma Capture Pro software on it. Not sure I want to do that, I'm not professional enough.

I think the Quattro goes up to 12X magnification for manual focusing; would that not compensate for the 'small screen' (just for focusing)?

[xpatUSA]

Cannot advise on the mirrorless, but when i want to absolutely nail focus on a DSLR, the camera is on a tripod and I use Live View zoomed to 100% view. never fails.

Richard and Peter, thanks for your input. Neither of my DSLRs have live view nor do they have EVF.

My other Sigma cameras are mirror-less but have fixed lenses.

[Manfred M]

I think the Quattro goes up to 12X magnification for manual focusing; would that not compensate for the 'small screen' (just for focusing)?

That looks like a very good approach. When I shoot at night, I do all my focusing manually using maximum magnification with LiveView. The only downside I have come across is that there can be a lot of noise visible at high magnification and that makes if more difficult to focus.

[Stagecoach]

That looks like a very good approach. When I shoot at night, I do all my focusing manually using maximum magnification with LiveView. The only downside I have come across is that there can be a lot of noise visible at high magnification and that makes if more difficult to focus.

The other downside is that unless your camera is on a very rigid tripod it can be very frustrating because the slightest movement of the camera whilst turning the focus barrel will be reflected in what you see as you adjust.

[Manfred M]

The other downside is that unless your camera is on a very rigid tripod it can be very frustrating because the slightest movement of the camera whilst turning the focus barrel will be reflected in what you see as you adjust.

Agreed. My tripod is rated at 30 kg / 66 lbs and the head is rated at 22 kg / 50 lbs. It has some lovely solid spikes that I use in the ice and snow in the winter or on grass when the ground is not frozen, so it does not move at all. There was one instance that I shot a series of images over a period of 90 minutes and the alignment from the first shot to the last shot were aligned to the pixel.

My other tripods are decent, but not in the same league.

[JBW]

Not possible with my existing DSLRs. However, the recent Sigma mirror-less sd Quattro ILC can be tethered, provided one carries a laptop with Sigma Capture Pro software on it. Not sure I want to do that, not professional enough.

I think the Quattro goes up to 12X magnification for manual focusing; would that not compensate for the 'small screen' (just for focusing)?

When I got my new camera the manual focusing went up yo 15x and on the LCD it made a significant difference. People here started noting that my focusing had really improved.

[xpatUSA]

When I got my new camera the manual focusing went up yo 15x and on the LCD it made a significant difference. People here started noting that my focusing had really improved.

Some people here know that I like numbers, for example this MTF versus that MTF, while others might prefer shrubbery shots to compare sharpness with.

Anyhow, back on topic, I was trying to manually focus a Pentax Super-Takumar 28mm on a wall target with a Sigma SD15. AF not possible, the Tak. has no electronics. But with the Sigma, a sort of AF should be possible by turning the focus ring back and forth until it beeps and a green light comes on in the optical viewfinder. So, l made sure the center-point only (a cross-type) was selected and then looked up the camera's sensitivity in the manual - a fairly good range 0 to 18 EV. Oh whoopee, I go because 0 EV is almost darkness well below the light impinging on my wall ...

... nope! No beeps, no green light, even tho' my old Sekonic tells me 7 EV's worth of exposure value is flooding my target. So I trained a few more lights on the wall, cranked down the lens from f/8 to f/5.6 and tried again. Sure enough, there were beeps and the green light lit, so I joyfully took a shot. I also took another shot focusing by eye through the finder, just to compare.

Hmmm .... which is which? ...



Yep, you guessed it; the left was what I got from the stupid green light and the right was from using my eyeball!

So, it looks like the Sigma AF sensor is easily fooled - or my simpleton's view of what a cross-type sensor can do is just plain wrong. I'm sure "most of us" know better.

[george013]

Some people here know that I like numbers, for example this MTF versus that MTF, while others might prefer shrubbery shots to compare sharpness with.

Anyhow, back on topic, I was trying to manually focus a Pentax Super-Takumar 28mm on a wall target with a Sigma SD15. AF not possible, the Tak. has no electronics. But with the Sigma, a sort of AF should be possible by turning the focus ring back and forth until it beeps and a green light comes on in the optical viewfinder. So, l made sure the center-point only (a cross-type) was selected and then looked up the camera's sensitivity in the manual - a fairly good range 0 to 18 EV. Oh whoopee, I go because 0 EV is almost darkness well below the light impinging on my wall ...

... nope! No beeps, no green light, even tho' my old Sekonic tells me 7 EV's worth of exposure value is flooding my target. So I trained a few more lights on the wall, cranked down the lens from f/8 to f/5.6 and tried again. Sure enough, there were beeps and the green light lit, so I joyfully took a shot. I also took another shot focusing by eye through the finder, just to compare.

Hmmm .... which is which? ...



Yep, you guessed it; the left was what I got from the stupid green light and the right was from using my eyeball!

So, it looks like the Sigma AF sensor is easily fooled - or my simpleton's view of what a cross-type sensor can do is just plain wrong. I'm sure "most of us" know better.

Or something else. The right image is more than 30% bigger.

George

[Manfred M]

Or something else. The right image is more than 30% bigger.

George

You might want to look up the term "focus breathing". George. That appears to be what we are seeing here.

[george013]

You might want to look up the term "focus breathing". George. That appears to be what we are seeing here.

I refer to the size, 995KB and 1310KB. Info in the pictures.

George