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Forum: Pentax Full Frame 06-03-2016, 01:14 PM  
Hey, isn't this 36 MP sensor supposed to out-resolve all legacy Pentax glass???
Posted By jsherman999
Replies: 84
Views: 8,839
I know, right? Everyone knows it's the Nike shoes that bring the game up to that level.
Forum: Pentax Full Frame 05-06-2016, 03:36 PM  
Tamron 28-75 and 70-200
Posted By jsherman999
Replies: 29
Views: 4,633
I use the Tamron 28-75 2.8 on 36MP D800 for all kinds of casual shooting, and it's great. There are bad copies out there, though.


Crop of above:


Forum: Pentax Full Frame 05-06-2016, 03:28 PM  
Pixel shift results from DPreview
Posted By jsherman999
Replies: 35
Views: 2,768
btnapa, you compared two different focal lengths from the same position, or moved back with the Tamron at 200 to preserve the framing? Neither is apples-apples.

I owned a perfect copy of the Tamron 70-200, and my 77 was sharper than the Tamron at 77mm through the entire shared aperture range (f/2.8+) I think I had a thread here where I compared my new tamron to a couple primes at those focal lengths, and the 77, M85 f/2, the Sigma 70 and another were sharper, but the Tamron beat all my Taks and other zooms.

I don't live in a world where an in-spec 77 is not 'good enough' for high-MP FF :)

It's going to resolve more and better than it ever has before, outside of maybe on the K3. Pixel peeping 36MP is going to show you things you never saw before, but you don't print or display 100% crops of test charts. The 77 (and 43, and 31) are great FF lenses even at 36MP, as long as they're not faulty and your AF is on-target.


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Forum: Pentax Full Frame 04-12-2016, 10:19 AM  
Does a larger sensor have effect on dynamic range?
Posted By jsherman999
Replies: 61
Views: 3,371
.

The short answer is, "Yes, a larger sensor will give you more Dynamic Range."

The main caveats being:

- If the sensors are of similar generation and technology (newer smaller sensors can beat older larger sensors)
- Assuming same exposure, framing, but not same DOF. (Meaning, same FOV and F-stop - don't compare different exposures and expect apples-apples)

It's not always true at base ISO - newest technology is often king there. As you move up the ISO scale, you see the effects of more total light in the image when taken at the same exposure, and the larger sensor shows it's advantage.

Bill Claff is an engineer who measures raw files from almost every body, calculates and then plots a measure called PDR (Photographic Dynamic Range) - he was doing that before DPR got in the game, but their screen tab graphs mostly mirror his findings.

Here we see the PDR of three cameras - MF 645Z (yummy), D800E and D7000. The D800e and D7000 have essentially the same sensor, one just larger:



Here's DPR's graph of DR for D800 vs D7000 - again, same pixel tech:



You can peruse Bill Claff's site or DPR (choose 'print tab' to see effects on whole image, not 'screen tab' which shows you 100% view) comparing different cameras of different generations - but what you'll find as a general rule is that with roughly same-gen cameras, you almost always see a DR advantage in the ISO range with larger sensors, even with varying pixel sizes. Very simply: Larger sensor = more total light gathered at the same exposure, which affects noise and DR.

What this means to you: The obvious. Say you have a K-1 low light shot at ISO 1600 - you would see noticeably more push-pull capability in that image than you would have with your K5 taken at the same FOV and exposure, recovering highlights a bit more, pulling more things from shadows before the image breaks down.

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Forum: Pentax Full Frame 04-12-2016, 09:44 AM  
New to Pentax FF? Legacy Lenses kit recommandations.
Posted By jsherman999
Replies: 28
Views: 3,439
I'd really like to know how the FA 20 f/2.8 performs on the K-1, and the F/FA 50 1.7.
Forum: Pentax K-1 04-02-2016, 10:03 PM  
Will autofocus work between K-1 and my Sigma 70-200mm f/2.8 EX DG HSM II Macro?
Posted By jsherman999
Replies: 29
Views: 3,719
You can expect that every lens that will AF on a K20D/K7/K50/K5/K3/K-whatever will AF on a K1.

If there's a FW-related bug with a particular K-mount lens it will be addressed.

The Sigma 70-200 f/2.8 and Tamron 70-200 f/2.8 will be smart and fun choices for the K1.
Forum: Pentax K-1 04-02-2016, 09:31 PM  
K-1 Post Traumatic Stress Syndrome
Posted By jsherman999
Replies: 88
Views: 6,064
...."Out For Delivery" nulls all the overworked registers in the brain and brings renewal.
Forum: Pentax K-1 04-02-2016, 09:23 PM  
The K1 will it breathe new life into focal lengths that have not been as popular?
Posted By jsherman999
Replies: 44
Views: 3,300
I like hearing this, because growing up, a 35mm camera and lens kit wasn't a trivial purchase among my family or even in my greater community - you were either 'rich' or an obsessive hobbyist if you had a 35mm camera. Being a participant in a forum of enthusiasts for the past 9 years has made question my own experience at times... like maybe I had it wrong. It's nice to see people who have a shared appreciation for the relative rarity of our hobby, and a big reason for that rarity is cost, if we're being honest.



Yes. Or to put it another way, it will allow a new avenue of appreciation that's really a walk down an old avenue.

.
Forum: Pentax Full Frame 04-01-2016, 01:11 PM  
f-stop/aperture differences APS-C vs. Fullframe
Posted By jsherman999
Replies: 83
Views: 4,974
But again, the chef or the Indy car driver doesn't deny the underlying reasons why too much salt will ruin the dish, or too much FP of force will pull him into the wall - they just apply knowledge gained from experience that maps to the underlying science. They don't actively deny that science exists, they just use they're own ad-hoc interpretation of it.

(BTW the composer example does not apply - there is no underlying mathematical and physical rule that describes in more detail what he/she does - a musical composition is purely art, purely subjective. I suppose one could come up with a mathematical formula that describes a cadence and chord change that would be most pleasing to most people based on a lot of data and surveys, but IMO music will always just elude an underlying quantitative order. Maybe. I hope. We'll see how they re-task the OK-Go cluster.)

Equivalence is actually very practical and probably makes itself most useful in the planning/buying stage - it allows you to set expectations about how buying anything might help or hurt you. It helps you figure out if someone is trying to sell you a bunch of BS. That's it. After the purchase, you're free to add your pinch of salt, and if you chose wisely, you'll find that you're a happier, less frustrated chef.
Forum: Pentax Full Frame 03-30-2016, 09:33 AM  
New glass - old glass. Which lenses should Pentax revisit?
Posted By jsherman999
Replies: 204
Views: 16,600
Yes, although they should be able to make a smallish, not-too-expensive (< $750) FA 20mm f/2.8, which would be a thrill to use on FF.

Re the K-mount 50 f/1.2 conundrum:



($200 and sweet :) )


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Forum: Pentax Full Frame 03-27-2016, 06:19 AM  
New glass - old glass. Which lenses should Pentax revisit?
Posted By jsherman999
Replies: 204
Views: 16,600
I'm continually hitting refresh on Amazon Prime until I see these ^ appear.
Forum: Pentax Full Frame 03-26-2016, 07:18 AM  
New glass - old glass. Which lenses should Pentax revisit?
Posted By jsherman999
Replies: 204
Views: 16,600
Whatever they do, they need to make sure their QA is as good as can possibly be. Moving from the MIJ FA Limiteds to the MIV ones resulted in several reviews (and many shooters) noticing a lack of sharpness, de-centering, etc.

There's no reason why the new manufacturing facilities and processes can't be brought up to snuff.
Forum: Pentax Full Frame 03-22-2016, 04:22 PM  
f-stop/aperture differences APS-C vs. Fullframe
Posted By jsherman999
Replies: 83
Views: 4,974
How do you just know how each performs? Underneath your 'just knowing' is an ad-hoc application of equivalence, gained from (likely) experience.

I think the difference is that you prefer to leave it as vague an estimate as possible, which is fine, but it doesn't make the definitions under it all 'meaningless', it just makes them unimportant to you.

As far as shooting goes, I rarely apply equivalence either, for what I do. If you're hitting a perf limit though and you're wondering if lens X on camera Y might give you better results for shooting situation Z, you'd be better off applying it more precisely before you buy. Or, not. Equations generally don't care if they're used. :)

Alan Oleson summed it up nicely on dp:

"We have just found a simple and practical tool to explain most of the differences which others seem to think are unexplainable and just some weird thing you have to accept when changing formats."


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Forum: Pentax Full Frame 03-22-2016, 01:03 PM  
K-1 So What Is Full Frame Going To Provide Over A Crop Frame DSLR
Posted By jsherman999
Replies: 312
Views: 18,208
Bring it back I sez! ;)
Forum: Pentax Full Frame 03-22-2016, 11:40 AM  
Are the extra dollars worth the upgrade to the full frame sensor?
Posted By jsherman999
Replies: 54
Views: 3,703
In probably most ways that matter to photographers, it's an 'upgrade', in that it provides all the shooting options you had with the smaller format and some new ones the smaller format doesn't provide. **

It provides the potential for less noise, more DR, more DOF control in the majority of shooting situations. How much of an upgrade it is depends entirely on the photographer and her use cases.

For a lot of people, the level of 'upgrade' it provides for their shooting scenarios isn't worth the cost. Knowing how to apply equivalence helps you figure that out - helps you manage expectations before you lay down the $$. There's a good example of this with a PF member I can provide.

** and this is without taking the 'upgrades' that the manufacturer may put in the top-line body, like better AF module, bigger VF, other options that go into the flagship.
Forum: Pentax Full Frame 03-22-2016, 08:13 AM  
f-stop/aperture differences APS-C vs. Fullframe
Posted By jsherman999
Replies: 83
Views: 4,974
Yes, but keep in mind how this would map to real-world shooting - you will rarely (outside of non-stacking macro) ever find yourself in a situation where you just can't stop down any more, that the smaller format allows you greater DOF that the larger format just can't physically match - because often when you're getting into those situations, hyperfocal has already kicked in and any 'greater DOF' the smaller format would give you is just theoretical.

What typically happens is this: You feel the need to get more DOF with the larger format, so you have the option of stopping down to match the DOF (and noise/DR) of the smaller format. Done. Same DOF for both.

Or:

You would like less DOF to diffuse the junk in the background more, or to make your lovely subject 'pop' out of the frame more - but the smaller-format lens is already wide-open. Larger format gives you the option of getting that extra stop less DOF as long as you have a lens that has the same FOV and max f-stop.

Divorce the argument from aps-c vs. FF - imagine yourself shooting with the Q vs. the K5. With available lenses, with your typical subjects, which would give you the feel of more 'DOF control', the Q or the K5?

Now, apply that answer to K5 vs. K1.

.
Forum: Pentax Full Frame 03-22-2016, 07:59 AM  
f-stop/aperture differences APS-C vs. Fullframe
Posted By jsherman999
Replies: 83
Views: 4,974
^ Well put.

.
Forum: Pentax Full Frame 03-22-2016, 07:50 AM  
f-stop/aperture differences APS-C vs. Fullframe
Posted By jsherman999
Replies: 83
Views: 4,974
Good idea. No big objections, quibbles below.



This isn't really wrong, but IMO will cause confusion because shooters will wonder why you didn't say, for example, "FOV and exposure" instead, with DOF just being derived from that. You can see why writing a simple equivalence article can be difficult, most people will agree with the underlying facts when it's fleshed out, but if those facts are presented in a way or in an order they're not used to, it creates churn.



Yes, but it isn't actually the ISO bump that 'creates' the noise, it's the shooting at lower exposure that does. The ISO bump just shows you the noise that you created by reducing exposure.



Equivalent brightness, yes. ('exposure' is technically only SS and F-stop)



Not just DOF - this also provides less noise and greater overall DR, when looking at sensors of similar generations.



People will argue this well and there may be too much to go into here, but one thing to keep in mind is that in order to take full advantage of the 'more magnification' to have to have correspondingly sharper lenses on the smaller format.



I think with the current choices, the only IQ-related reason to run both systems (vs. just K1) would be if you sometimes absolutely need the higher pixel density of the K3 and have the lenses and tripods and technique where it can really make a difference, and you don't want to or can't buy the longer lenses for FF that would even things out. Otherwise, the K1 can do everything the K3 can, and some things it can't.
Forum: Pentax Full Frame 03-21-2016, 05:16 PM  
K-1 So What Is Full Frame Going To Provide Over A Crop Frame DSLR
Posted By jsherman999
Replies: 312
Views: 18,208
645Z would (probably,) but 645D is a much older CCD sensor. It's giving up some or most of it's 'larger' advantage because of that.
Forum: Pentax Full Frame 03-21-2016, 04:47 PM  
f-stop/aperture differences APS-C vs. Fullframe
Posted By jsherman999
Replies: 83
Views: 4,974
Right- at the same exposure (f-stop and shutter speed) and assuming you're after the same FOV, the larger sensor will gather more light (and have less DOF.)






QuoteQuote:


Ok, now I try to articulate my question. will there be a difference in exposure time (can it be shorter) when using a full frame camera while using the same aperture on an APS-C camera shooting the same thing. ... Will it have a difference since the sensor has a greater area and captures more light?



Well... sort of. It can be shorter at the same f-stop and FOV, but you lose any noise advantage then because you'd have to boost ISO to maintain brightness, and that would show you the additional noise you introduced by using less exposure.

Also, a quibble on terminology - a wider aperture doesn't give you more 'bokeh', it changes the DOF. 'bokeh' has a distinct meaning from DOF. A scene with exactly the same DOF can have vastly different bokeh quality, it's lens-dependent and sensor size-independent.
Forum: Pentax K-3 03-21-2016, 07:21 AM  
Neocamera - K3 vs. K5IIs
Posted By jsherman999
Replies: 59
Views: 9,165
I suppose. I would be very surprised to find a significant variance in noise/DR between examples of the same model, though. AF, metering, a few other things possibly, but noise introduced into the processing chain from partially failing ASICS? Doesn't seem highly likely... The fact that we haven't heard about this as an issue or a worry from any of the review sites or from users/forums suggests that's the case too. Or at least I haven't heard about that issue, perhaps I'm out of the loop on that.
Forum: Pentax Full Frame 03-20-2016, 02:55 PM  
Why the 'screen tab' on DXO was not meant to represent camera output
Posted By jsherman999
Replies: 58
Views: 2,941
I can't wait to upgrade to a C64, I'm still using my Vic-20. 36mp is a b***h, it takes me 400 cassette tapes to store one image.
Forum: Pentax Full Frame 03-20-2016, 08:19 AM  
K-1 So What Is Full Frame Going To Provide Over A Crop Frame DSLR
Posted By jsherman999
Replies: 312
Views: 18,208
My current Fav Nat Geo shot was taken with an RX-100:



Don't know what PP went into that, but one thing that strikes me is that there's 'enough' DR to make the image work. RX-100 did a great job. Photographer did a one-in-a-million job.


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Forum: Pentax Full Frame 03-20-2016, 07:24 AM  
K-1 So What Is Full Frame Going To Provide Over A Crop Frame DSLR
Posted By jsherman999
Replies: 312
Views: 18,208
Selectively quoting again? Why don't you quote some things from this thread, in which your... EDIT "interesting"... theories were not-so-gently shown the door (big D is the 'unknown member' in that thread, becuase he was later banned as a troll.) Link to major fail

Here's how this thread/argument has progressed, btw:

Gallon and quart full of water sit next to each other.

Guy1: As you can see, an Oz of water taken from each of these containers has the same mass and density, so the containers are equally capable of carrying water.

Guy2: What do you mean equally capable? The Gallon container holds more total water.

Guy1: What is this concept of "Total Water?!" Can't you see the individual ounces are EXACTLY THE SAME?

Guy2: Of course, but if you weigh both containers, the Gallon weighs more. It's got more volume, same quality of water inside, means more total water.

Guy1: It weighs more simply because it has MORE OUNCES!

Guy2: Huh?

Guy1: For example if you simply put MORE OUNCES IN the QUART CONTAINER, it would match the gallon in weight! LULZ ROFL! It's about the # of ounces, and the quality of each ounce! You Total water guys kill me!

Guy2: How would that work, exactly, putting more ounces into a quart?

Guy1: Well if such a beast existed maybe denser water maybe, that's all they would have to do and then they would weigh the same!

Guy2: OK... Setting aside the fact that an Oz is volume... couldn't they just put this 'denser water' into the gallon then too?

Guy1: ROFL! You guys!

..etc...

An actual example of that last part:



... ^ this imagines a magical or at least yet-to-be-invented pixel with the current efficiency and performance of the E-M5's current pixel (or maybe even better efficiency, who knows what's being imagined,) but made smaller to fit 50MP of them into that same micro-four-thirds sensor area.

Why not take these magical yet-to-be-invented pixels and put them into a larger sensor, thus maintaining the same advantage that exists today?

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Forum: Pentax Full Frame 03-20-2016, 06:09 AM  
K-1 So What Is Full Frame Going To Provide Over A Crop Frame DSLR
Posted By jsherman999
Replies: 312
Views: 18,208
Pasting things out of context to try to help yourself? I see why you stopped there :



Good try, though!

(Also, I think Jack Hogan would be surprised to find that he's an equivalence denialist, which I assume you're also implying. ;) )

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