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09-03-2015, 05:48 AM   #1
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Manual Focusing

I invented autofocus, in the '70s. Really, I did. Well, in my head, anyway.

I recall struggling with with the darkening of a split-image or microprism focusing aids, or straining my (then very good) eyes while trying to feel absolutely confident that the split-image is not, or that the microprism is as clear as it can possibly be. I then imagined a world in which electronics would perform this function. The rest, as we all know, is history

Sadly, all is not perfectly good. The state of current AF technology is such that it sometimes misses perfect focus. However, my eyes now are definitely not better than they were 40 years ago, so AF, as imperfect as it may be, is nevertheless a welcome feature.

I do see here at PF that there are many who use manual focusing. I suppose in some cases this is simply due to the use of manual focusing lenses, but I also get the impression that some users prefer MF. This, I would assume, is due to being able to achieve more perfect focus than what would be reached using AF. So my question is, for people who have not replaced the focusing screen with KatzEye or similar: when using MF, do people rely on the AF indicator, or on what they see in the viewfinder? And if the former, is the indicator actually more precise when used manually than in conjunction with any AF motor?

09-03-2015, 06:08 AM   #2
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I guess the AF indicator, or catch-in focus still uses the same AF sensor, and it is actually not as accurate or fast as AF itself.
original focus screen is not for MF. I am sure it is not as accurate as AF if the lens is fast.
MF or MF override is useful only when AF system is confused, such as birdS behind leaves, people behind window...But to be honest, 99% chance, I just half-press the shutter button and force the camera to redo AF, instead of MF in these cases, even the lens has quick shift system.
I install split screen on cameras I want to MF, and use them for fast MF lenses.
09-03-2015, 06:15 AM   #3
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QuoteOriginally posted by grahame Quote
I guess the AF indicator, or catch-in focus still uses the same AF sensor...
Yes, and this raises the question of whether AF inconsistency is due to inadequacy of the sensor or the motor.
09-03-2015, 06:31 AM   #4
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I use manual focus almost all the time since I have been using my Topcor lens (converted to m42). I have much higher keeper rate than using AF lenses. I use PDAF focus confirmation and catch-in-focus feature on the camera. Since I can not release the shutter unless the camera recognizes that focus is achieved, it works all the time unless I am being careless and let the focus point falls into an area not intended (here is an argument on 'when smaller focus point is not better').

I don't use any special screen for manual focusing only installed the better viewfinder diopter. IMHO, with manual focusing I can control which direction (turning the focus ring) to achieve focus, and depending on the DOF, it is less prone to error (focusing on wrong area).

09-03-2015, 07:03 AM   #5
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firstly - thank you for the autofocus thingy; it's pretty cool...

QuoteOriginally posted by bxf Quote
I do see here at PF that there are many who use manual focusing. I suppose in some cases this is simply due to the use of manual focusing lenses, but I also get the impression that some users prefer MF. This, I would assume, is due to being able to achieve more perfect focus than what would be reached using AF. So my question is, for people who have not replaced the focusing screen with KatzEye or similar: when using MF, do people rely on the AF indicator, or on what they see in the viewfinder? And if the former, is the indicator actually more precise when used manually than in conjunction with any AF motor?

I use MF lenses quite a bit and noticed that my focus fail rate was pretty high... but I upgraded my viewfinder to the Pentax magnifying viewfinder and it has helped tremendously...

I'm a little anxious at replacing the viewing screen... but maybe in the future...

I also do rely on the focus confirmation in my K-50 - it's pretty reliable, but I use it mainly to know that I'm in the region of focus, and rely more on my left eye after that...
09-03-2015, 07:18 AM   #6
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QuoteOriginally posted by aleonx3 Quote
...Since I can not release the shutter unless the camera recognizes that focus is achieved, it works all the time...
This must still use the same hardware/software components as when using "normal" AF, so why would this be more precise?

QuoteOriginally posted by aleonx3 Quote
I don't use any special screen for manual focusing only installed the better viewfinder diopter.
What is this?

---------- Post added 03-09-15 at 15:20 ----------

QuoteOriginally posted by pepperberry farm Quote
firstly - thank you for the autofocus thingy; it's pretty cool...
lol. My pleasure, glad you like it
09-03-2015, 07:36 AM   #7
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Most of the time autofocus works pretty well. When you start confusing that sensor - trying to focus on a striped brown and green dragonfly perched on grass in front of brown and green grassy foliage - well, the computer has no idea what it's looking at. That point is where it's good to quickly switch to MF and get your shot. Quick is a relative term, of course. In the bright sunlight I have no problem with this. When the subject is behaving I have no problem. If it's breezy or the subject keeps moving it's much more difficult. It was difficult in the film days with big viewfinders and split-focus screens...

Light is the tough thing, though. As usual.
09-03-2015, 07:37 AM   #8
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I do not consider myself a good MF photographer but I do know when AF fails I wish I had been using MF.

This is what I know:

1) like you my eyes are not what they used to be so I use MF combined with LV (live view) when AF is unreliable. This works best with stationary subjects or doing macro images.

2) I have found the LV focus to be slower but more accurate than using the focusing screen.

3) I also shoot micro 4/3 and AF on my Olympus OM-E M10 is far more accurate and just as fast than than the one on my K-3. The AF on the Pentax is the biggest weakness of the Pentax system. I don't mind the wait much, all I want is accuracy. Note: The Olympus OM-E M10 does not have the K-3's resolution, dynamic range or low light performance yet I rarely miss a shoot with my Olympus f1.8 primes, even wide open.

4) I get more consistent focus with some lenses than others. In general my Pentax primes have the best focus accuracy with my Tamron zooms having the most inconsistent focus. The Sigmas are good but very slow to focus in LV even if they are accurate most of the time.

5) Way too many times I take a picture and think all is well from looking at the 3" preview screen and when I get home I see the eyes were not perfectly in focus. Sure, most of the time it was greedy shoot with a small DOF but I pointed the focus right at the eyes. We really need better tethering on the Pentax cameras so we can get bigger screens to preview our images. I have tried to use MF in LV + Focus Peaking to improve accuracy of portraits with small DOF but I find the process is not as seamless as it can be.

6) MF using the green light is not more reliable than AF. It does help when the AF can't find your subject like shooting through a fence or a glass window.

7) MF is popular for street photography (wide angle lenses, lots of DOF), landscape photography (set lens to infinity) and macro photography but the later is almost always used in combination with LV. Other kinds of photography like wedding and portraits (what I mostly do) use AF because the short time between shoots.

My best advice:

1) get a Pentax K-3 or K-3 II, they have the best AF performance and accuracy.

2) Get some Pentax DA primes, they don't have to be limited primes but you will like them if you get them. The FA primes tend to have lower focus accuracy than their DA counterparts but it is not a deal breaker by any means.

3) Use LV when you can, it is slower but more accurate.

4) Don't be like me, don't be greedy with DOF and accept less quality bokeh (don't shoot wide open, close that aperture) in exchange for a better chance of getting that perfect head shoot or portrait.

5) Use wider lenses, they have more DOF and are more resistant to AF errors. Then again, it depends on the photography your doing too. I rarely miss a shoot with my Pentax f3.2 21mm limited while I have to be extra careful with my 70mm f2.4 limited if shooting wide open as it has such a small DOF.


Hope this helps.

09-03-2015, 07:52 AM   #9
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QuoteOriginally posted by bxf Quote
This must still use the same hardware/software components as when using "normal" AF, so why would this be more precise?


What is this?
I have O-ME53 diopter on my viewfinder.

I am not sure how the AF algorithm works, it may be simple or it could be complex taking into account the DOF (optimally in the middle). With manual focus, I have better control (turning focus ring from near-to-far or far-to-near), whereas with autofocus, sometimes, the focus lands on the wrong place (example, the background between two subjects), in both cases, I have focus confirmation. So IMO, manual focus is more precise....

Last edited by aleonx3; 09-03-2015 at 08:15 AM.
09-03-2015, 08:38 AM - 1 Like   #10
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I have an O-ME53 and a S-Type focussing screen.

I focus manually, not all the time, but, i don't know, 30-70% of the time.

I do it because
- i worked with a K10D for years, and the focus wasn't so good a lot of times so yes in part because i achieve better focus manually (it needs to be a habit though, when i haven't focussed manually for a while i suck at it). However i just got a K3 that i'm going to test drive in a portrait shooting soon, so maybe that reason is going to go away
- i have an M50 1.7 and i don't own a normal with AF. when i want that focal length, i have to mf.
- i really like manual focussing. not only do i enjoy it, but (ok this is going to sound stupid) i think it lets me feel the image more while i take it. it's like the difference between playing an instrument and clicking on a computer that simulates an instrument. with the first the instrument feels like an extension of myself. told it it would sound stupid :-)
- when i screw up focus, at least i'm angry at myself. when the camera screws it up, i'm angry at my camera. with the first, i feel like i'm making mistakes and learning from them, with the second i just feel like i've spent a lot of money on equipment that lets me down :-)
- i want technical stuff out of my photography process as much as possible. it's a philosophy, i think technical stuff distracts you from being creative.

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09-03-2015, 08:45 AM - 1 Like   #11
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I've had the very high quality Hua Guang 1.3x VF magnifier on my cameras for several years - permanently attached. This helps with MF focusing, but you still don't have precision with the faster lenses. Overall, the significant improvements in Live View since the K-5 series (everything that includes focus peaking) allows for the greatest precision in focusing on static subjects. The Live View system - usually magnified - is especially helpful for textured surfaces or when using lenses at f/2.8 or faster.

I don't find focus points to be at all precise if I have a very small point of focus in the frame - such as the pupil of an eye, although the K-3 appears to have improved the situation somewhat. Overall, I probably shoot in MF about 30% of the time (including switching an AF lens to MF). If I was shooting more action, I'd be shooting AF nearly all the time. I find C-I-F to be unreliable (not sharp enough for me on well over 90% of the shots). Finding out what works best for a particular situation comes down to a lot of trial and error. Experimenting improves my keep rate - even as the human eyes have declined gradually.

Keep in mind that a lot of fast MF glass has at least some aperture focus shift. This is especially true for the Samyang (Rokinon, etc.) 85 f/1.4. You are best off stopping down the lens to nail exact focus; the shift is especially apparent in the range f/2.2-3.2 - beyond that the greater DoF begins to negate the shift.
09-03-2015, 08:47 AM - 3 Likes   #12
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QuoteOriginally posted by Bromberger Quote
- i really like manual focussing. not only do i enjoy it, but (ok this is going to sound stupid) i think it lets me feel the image more while i take it. it's like the difference between playing an instrument and clicking on a computer that simulates an instrument. with the first the instrument feels like an extension of myself. told it it would sound stupid :-)
bromberger

doesn't sound stupid at all - I feel the same way about using manual lenses: it makes me really work at and be aware of the entire process, from seeing what I want to see in my head all the way until I press the shutter button... it's all on me....
09-03-2015, 09:07 AM   #13
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I love manual focusing, and use it most of the time if I am not rushing or shooting things that move. The magnification + focus peaking abilities of the K-3(ii) make it easy and quick It is invaluable with a lower light, low contrast subject which can cause the AF system to rack back and forth.
09-03-2015, 09:24 AM   #14
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It might be my Minnesota bias, but Jim Brandenburg influenced me greatly by his amazing one photo a day project Chased by the Light. Sort of the slow food movement for photographers. I did it (photo a day) for about 10 days - and it made me a better photographer. Perhaps I should do that every year. (I wasn't as good at it as Brandenburg, but my comedic excuse is I was in northern New Mexico at the time, not Minnesota.) While I don't recall specifically, I suspect that I was manually focusing those images!
09-03-2015, 10:04 AM   #15
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QuoteOriginally posted by cali92rs Quote
magnification + focus peaking abilities of the K-3
magnification on the screen is (said) much better on k3 or ks2. Adam confirmed new pentad cameras magnifies the image from what sensor sees, not just enlarge the small JPG generated for review, as all older pentax cameras do. That is one of the reasons I bought KS2. still waiting for delivery...
But, I still like to hold the camera close to my face and use OVF. I don't feel steady enough without the extra support from my forehead and nose. reaching the camera out at ram distance is still point and shoot style for me.
I found the EES screen is very fast, and split screen is very accurate if you calibrate them. Little bit challenging for very wide lens because everything is so small, but AF or focus peeking struggles here also. DOV is larger though.
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