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02-27-2014, 04:39 PM   #1
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Manual focus tips on K30, 18-135mm WR lens

Hello everyone,

I really need some tips on the manual focus on K30 with 18-135mm WR lens. The reason being, I had a bad experience with auto-focus during low light condition and although the autofocus locks on the subject, the picture is still out of focus when viewed on bigger screen. Also AF took way too much time to lock on the subject and I had missed some great shots due to the delay.

I tried manual focus and its only 50% chance of getting the picture right. Hence wanted some tips regarding the same since I want to avoid auto focus. I tried focus peaking with live view but to be honest, I dont see any difference with the contrast. Not to mention, I prefer view finder always. Any tips on improving manual focus would really help.

Regards,
Jai

02-27-2014, 05:20 PM - 1 Like   #2
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Here is the sad news:
  • Manual focus using focus confirm or Catch-in-focus (CiF) are not a good solution since neither will work any better than the camera's AF system
  • Focus peaking in live view is very accurate, but can be hard to use in some light or off-tripod
  • Manual focus in the viewfinder using the stock focus screen is about as bad as using the AF system
The reasons for the last bullet point are complex, but it is enough to say that the stock focus screen has certain design features that increase its brightness and contrast, but at the cost of accurate depiction of depth-of-field (DOF). The stock screen yields an apparent DOF equivalent to f/4 or narrower. This is true even when using a fast f/1.4 lens. The result is a huge loss of precision and the inability to actually do fine focus.

For example, when I bought my K10D back in 2007, I was very disappointed in the performance of many of my faster lenses that I had successfully used on my K-mount film cameras. I simply could not get consistently sharp photos. That all changed when I replaced the stock screen with one of more traditional design and having the standard focus aids found on almost all manual focus SLRs dating back to the 50s (split-image/microprism). Worth it? Absolutely, no question.

I use the Katz Eye screen with Optibrite treatment.* I know there are several users on this site that are happy with less expensive options from focusingscreen.com. I personally would caution against the eBay merchants, but that is just my opinion and is not based on experience.


Steve

* Katz Eye Screen for K-30
02-27-2014, 05:31 PM   #3
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All I can say is lots of practice. I haven't tried the 18-55 kit lens, I used it on auto a few times but that's it. But with my manual lenses i Had used on the K-x for 3 years, I had trouble till I got familiar with the K30 and could see what to look for. Once you learn the camera and get accustomed to what it looks like you should be able to get better results with manual focus, but don't expect to get every shot just right. 40,000 shots with the K30 and I still get plenty out of focus shots.

Don't know how to explain it, but now I can usually see when it's in focus, especially with macro shots and close subjects. It takes practice thought to get the hang of it.
02-27-2014, 05:40 PM   #4
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Sharp or Not?

Hello Jai, welcome to the Forum!
Yes, M/F an A/F lens is no fun, especially in low light. For all the reasons Steve mentioned, plus one more; Slow max aperture lens. Focusing would be much easier under those (or, any) conditions with an f/2.8 135mm or anything shorter and faster.
Which helps lead to a common ailment called LBA.
In the meantime, add a + 1 for KatzeEye split-prisms, they work and in very demanding conditions, too. You're lucky that the K-30 has an interchangeable screen, some mid-range DSLR's don't. If your budget allows, it's a worthwhile investment.
And one or two M/F Legacy primes wouldn't be a bad idea, either. With or without the screen upgrade, faster M/F primes will help all your low-light work.
Good Luck!
Ron

02-27-2014, 06:10 PM   #5
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These are exactly the reasons I want to upgrade to a K-3, to get that sweet -3EV focusing. K-5II is not an option for me because I use focus peaking quite regularly for closeup/macro work.
02-27-2014, 08:02 PM   #6
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I bought a cheap focusing screen for my K30 and it is just fine. Granted, I have not used the Katzeye or focusingscreen.com products, but I'm comfortable not knowing what I'm missing... Green hexagon, red square, in-focus beep, split prism and my eye are all in perfect agreement, so I hit the $35 focusing screen jackpot, as far as I'm concerned. The stock focusing screen was fine, but the split prism is really helpful, especially in dim situations or for objects at a distance.

Practice and a steady hand are what you need.

Also, you may have the odds stacked against you with an auto-focus lens. In my experience, auto-focus lenses have focusing rings with a very short "throw" and it is hard to fine-tune your focus manually. Even a small movement of the ring pushes you past your desired focal point. The longer throw of the focusing rings on manual lenses is what I prefer, but your experience may be different.

It's all going to come down to giving it an honest try. :-)

(Also, focus-peaking in live view mode has made shots that I would not have been able to get peeping through the viewfinder. Try it all!)
02-27-2014, 08:08 PM   #7
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Thanks guyz. That is a lot of information. To be honest, until now I didn't know about the interchangeable screens.I actually thought 18-135mm WR lens would be an all-round lens but had issues during dim light condition and with sharpness on the portraits. And now looks like manual focus is a whole different thing.

So am not sure if I need to go for a different lens if interchangeable screen was not one of my option.
02-27-2014, 09:43 PM   #8
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QuoteOriginally posted by jaikumarr18 Quote
Thanks guyz. That is a lot of information. To be honest, until now I didn't know about the interchangeable screens.I actually thought 18-135mm WR lens would be an all-round lens but had issues during dim light condition and with sharpness on the portraits. And now looks like manual focus is a whole different thing.

So am not sure if I need to go for a different lens if interchangeable screen was not one of my option.
I have the same lens (18-135). In low light, I just boost the ISO to 1600 and my shots are ok. Try to focus on something white and that really helps.

02-28-2014, 07:37 AM   #9
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QuoteOriginally posted by jaikumarr18 Quote
Thanks guyz. That is a lot of information. To be honest, until now I didn't know about the interchangeable screens.I actually thought 18-135mm WR lens would be an all-round lens but had issues during dim light condition and with sharpness on the portraits. And now looks like manual focus is a whole different thing.

So am not sure if I need to go for a different lens if interchangeable screen was not one of my option.
One thing you may want to check is whether your lens is front or back focusing. Under bright light, the lens may stop down, and the increased DOF may mask this problem. Under dim light, with the lens more wide open, the lower DOF may reveal a problem that is there all the time. You may just need to fine tune the autofocus on the camera for that lens. If it turns out that it's not a front/back focus problem...

I don't own that particular lens, but no lens is going to cover every base. There's always a tradeoff. That lens has a fairly wide zoom range and is relatively inexpensive, so the tradeoff is that it doesn't have a
wide minimum aperture. It's not a fault of the lens - this is the nature of the physical world we live in and the trade-offs that have to be made.

A wider minimum aperture will give you a brighter view through the viewfinder, which may help with manual focusing.
But you'll either have to pay more for the lens, or give up some of that zoom range. And it might end up being bigger ( depending on whether or not you've given up zoom range ) Those are the trade-offs.

I've considered replacing my focus screen as well. Another less intrusive option that I've seen recommended in the forum is a viewfinder magnifier that you attach externally. I'm debating trying that option as well.

Using focus peaking in live view really is a nice option if you can make it work. I'm usually shooting outdoors in bright light, so it doesn't work for me because I can't really see the screen most of the time.
One of those hoods that goes over the LCD screen isn't really practical for me either, unfortunately.
02-28-2014, 08:08 AM   #10
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The expensive (and best long term) solution would be a fast lens...50 1.8 or 35 2.4 are a couple of relatively cheep options. Getting lenses that function at 2.8 or faster can be a big boost to the AF system.
02-28-2014, 02:02 PM   #11
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QuoteOriginally posted by normhead Quote
The expensive (and best long term) solution would be a fast lens...50 1.8 or 35 2.4 are a couple of relatively cheep options. Getting lenses that function at 2.8 or faster can be a big boost to the AF system.
I checked the prices of few of the prime lenses..... 50 1.4 is costing around AU$400 and 50 1.8 is costing around AU$200... The sharpness seems to be the same on both but 1.4 got shallow depth of field. Also checked 55 1.4 and its costing around Au$850.. Hence am not sure which is the right investment.....Go for prime lens or External flash or interchangeable screen????
02-28-2014, 06:39 PM   #12
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Interchangeable screens are from Katzeye and Focusing Screen.
Focusing Screen

I have used this on my K5 and it is a great help with MF and even AF lenses in low light. Planning to get one for my K30 in near future.
02-28-2014, 07:22 PM   #13
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I seem to be able to evaluate focus without a focusing screen, I'm sure one would be nice but, for macros etc. I seem to get along without it. And, flash doesn't really help you focus. I have a couple external flashes and a couple of slaves, and hardly ever use them. If I need flash, usually I just make do with what's on the camera. And I'm definitely not going to mess with manual focus on the grand kids... or my porch birds...but hey everybody is different. I just hate flash, and flashed images in general... flash to do it right is as much work as a full light set. But everyone has their own approach, and preferences. And I've always been natural light kind of guy, so fast lenses are what appeals to me.
03-01-2014, 10:02 AM   #14
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QuoteOriginally posted by jaikumarr18 Quote
I checked the prices of few of the prime lenses..... 50 1.4 is costing around AU$400 and 50 1.8 is costing around AU$200... The sharpness seems to be the same on both but 1.4 got shallow depth of field. Also checked 55 1.4 and its costing around Au$850.. Hence am not sure which is the right investment.....Go for prime lens or External flash or interchangeable screen????
Note that the other thing you get with the 1.4 version is full frame compatibility, aperture ring, etc, so you can use it on a FF film camera, or on some future FF Pentax DSLR.
Unless I'm mistaken, the 1.8 version is a DA lens, and therefore, won't really work on a FF camera ( at least, not as intended - I'm guessing a future FF DSLR will probably feature a crop mode for
compatibility with DA lenses ). So that's something to consider when making a decision. The F1.8 will give you a really bright viewfinder - a huge difference compared to the zoom lens.

It's going to be tough for someone else to tell you what the right investment is. Personally, I like having the bright viewfinder that a fast lens gives you. Even if it isn't always needed for focusing, it makes for
a more pleasurable shooting experience ( IMHO ). But it does ( generally ) cost more, and the lenses are usually larger/heavier.

As I said, I have yet to pull the trigger on a focus screen and/or viewfinder magnifier. Unfortunately, with a lot of these things, the only way you're ever going to know if a particular approach is going to benefit your personal shooting style is by trying it out.
03-01-2014, 05:28 PM   #15
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One thing I forgot to mention that helped me a lot, is to focus in front of and behind the subject a couple of times, you'll get to know how it looks when it comes into focus. Faster focusing lenses give me more trouble than slower ones. Too easy to pass it up...
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