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01-19-2018, 05:28 AM   #1
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2 questions about KP

Hello, I have recently upgraded from a k20d to a KP (wow what a difference holy moly I was in the stone age)

1. This is my first camera with live view. It is my understanding that live view uses a different focusing system than using view finder? Is this the case? Is it better/worse or just "different"? Perhaps I have misunderstood this one.

2. Electronic shutter. 2 questions. One, why would one not exclusively use this feature? Two why is the much advertised 5 axis shake reduction not available for use when using electronic shutter?

Thanks for any help! I am an amateur figuring out all this stuff slowly on my own so feel free to dumb things down!
Michael

01-19-2018, 06:08 AM   #2
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I can help with 1. I believe there is generally a noise or other IQ penalty for electronic shutter use (such as rolling shutter) , with 2. I'm be guessing but I wonder if it would be too much for the camera to process moving the sensor so quickly and reading (presumably at a higher speed to prevent rolling shutter) the data.

However I'm no engineer and definitely not an expert. Just an amateur.
01-19-2018, 06:13 AM   #3
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QuoteOriginally posted by RosieSC Quote
1. This is my first camera with live view. It is my understanding that live view uses a different focusing system than using view finder? Is this the case? Is it better/worse or just "different"? Perhaps I have misunderstood this one.
Live view uses Contrast Detection and "normal" AF is Phase Detect. They work differently. CD AF is more slow, but is always accurate. But it needs contrast, so focusing on a beige wall will not work well. PD AF is faster but it might have a lens bias, so some lenses might consistently front or back focus. But most modern DSLRs have a Focus adjustment feature to help against this. They are "different" and each has its pros and cons.
On a DSLR you will be using PD AF most of the time, since you will not be using live view so much. CD AF is fine for when you have tripod and stationary subject
No need to worry about this. You will learn how to use them when you get the camera. AF is not magic, its a tool you have to learn to use so that it gives you what you want.

KP is a good camera, enjoy
01-19-2018, 06:35 AM   #4
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QuoteOriginally posted by RosieSC Quote
Hello, I have recently upgraded from a k20d to a KP (wow what a difference holy moly I was in the stone age)
Can't help you as I eventually decided on the K-70 over the KP but couldn't help but noticing you held out with a K20D until now - possibly my all-time favorite Pentax body ever owned. Any I hear you about coming from the stone age but I still miss the K20D/K10D form factor and the solid, almost brick-like feel of that camera. Congrats on the new KP and happy shooting!

01-19-2018, 06:41 AM   #5
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Thanks newmikey! Hopefully I will still use it. About to have my first child so I got upgrade-itis with the hopes of shooting video (though admittedly the reviews of video on KP were horrific and I will prob just use my iPhone for this) but it helped me convince my wife
Of course now I want a new lens to shoot the little guy thinking about the pentax 20-40 as I have the FA 1.9 43 and the f4/300 (as well as a tamron 17-50 lens I never use which I can sell hopefully)
01-19-2018, 08:11 AM   #6
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QuoteOriginally posted by RosieSC Quote
1. This is my first camera with live view. It is my understanding that live view uses a different focusing system than using view finder? Is this the case? Is it better/worse or just "different"? Perhaps I have misunderstood this one.

2. Electronic shutter. 2 questions. One, why would one not exclusively use this feature? Two why is the much advertised 5 axis shake reduction not available for use when using electronic shutter?

1) as others indicated CDAF is used in live view. It uses the actual sensor with the shutter open. To take an exposure the shutter must close and reopen if using the mechanical shutter. CDAF typically is accurate but sluggish and slow to lock focus. PDAF uses sensors in the viewfinder prism area. The sensors are not precisely calibrated at the same distance as the sensor (they are close but there are tolerances for small differences). Given the high resolution of modern sensors this means that small variations in lens mount and camera mount give slightly longer and shorter distances from the lens to the sensor which leads to front and back focusing inaccuracy. For this reason you can fine tune lenses that have a way to be identified (chip) or even make a global adjustment.

2)Lookup rolling shutter. Because the electronic shutter isn't read out as a single operation, the reading of strips of data can lead to this effect. The motion of objects can appear to bend objects etc. As they move between the reading of data their position changes how they look.
01-19-2018, 12:04 PM - 1 Like   #7
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QuoteOriginally posted by RosieSC Quote
2. Electronic shutter. 2 questions. ... Two why is the much advertised 5 axis shake reduction not available for use when using electronic shutter?
It takes a good long while to scan the image captured on the sensor in electronic shutter (ES) mode. Longer than the shutter speed you've set. You could actually manage to move the camera (I always do) before the scan of the image is done and shake reduction cannot compensate for that. Which probably is why it is disabled by default.

If you shoot at, say 1/250s with ES, each part of the image will look as if exposed at 1/250s (e.g. motion is frozen in any part of the image), but it takes much longer than 1/250s to read the sensor from top to bottom (the time is not specified by Pentax, but we're talking something in the 1/10s range). So the time difference between capturing the top part of the frame and the bottom part is much longer than the shutter speed set. Bottom line, each part of your image will be sharp (no motion blur), but the overall image may be distorted either because you moved the camera or because the object moved.

Electronic shutter may benefit shooting stationary objects when using a tripod, but not much beyond that. As you can tell I've been quite disappointed by ES which I once thought would be the answer to vibration issues caused by the mechanical shutter.
01-22-2018, 09:46 PM   #8
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Your thoughts regarding the DA 20-40mm f/2.8-4 are very good, being that this lens matches the compact nature of the KP so well. It also delivers very fine image quality. It does offer a fast, wide aperture of f/2.8 at its short end, and f/4 at 40mm, but this is still very good because the KP's higher ISO performance can compensate enough to equal a constant f/2.8 on other cameras. The Tamron 17-50mm is a fast, constant f/2.8 lens, which I learned lately is prone to underexposure, so it may work out to f/3.2 equivalent. You may not use such a lens now, but if you wind up doing more low-light work, or fast-action at indoor venues or in dimmer outdoor lighting, it might come in handy. It also provides significantly wider angle- 17mm vs.20mm, and a bit longer at 50mm, which may actually test a bit shorter. Nonetheless, it would be a special-circumstance lens, while the very fine DA 20-40mm Limited is a better all-around, very sharp lens that is very compact for great carrying on the KP, and having WR.

I recommend going into the Custom Image menus, via the info button, this being the first section in the quick links screen. Hit ok to access all categories in this section. The first category is "Bright" which the camera is set on by default. Hit info again to open its menu. Use the 4 buttons around the ok to navigate. Use the down button to get to "S", which is up by +1 by default. Then use your thumb dial to put an "F" by the "S" to set Fine Sharpening. Now you are done with this category, so hit ok to return to all categories. Use your right button to move to the next, which is "Natural". hit info again to open it and move down as before. All are at center position by default. Repeat setting "F" by "S" for Fine Sharpening here also. Now hit ok, then using your left button, set your camera back to "Bright", then just shut off your camera, which will exit the quick links screen. You are now set for best fine detail in your images.

I am very familiar with the K-20D. I bought one new in I think 2008 in a great closeout deal when the K-7 was coming out. It was a pleasure to use over numerous years, and is still a very nice camera. I subsequently wound up with a K-5 IIs, a very fine camera. But the KP is capable of superior image quality and has many feature updates and capabilities, yet in a more compact, very well-built body. So I bought one as well, and I am very pleased with it. Its shutter, like the K-5 series and the K-3 series, is very quiet. I have not experienced or heard of any vibration issues. When using slow shutter speeds on a tripod, mirror lockup is available, even through the 2-second timer setting, if not using a cable release. Welcome to Pentax Forums!


Last edited by mikesbike; 01-22-2018 at 09:52 PM.
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