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Forum: Pentax DSLR Discussion 03-08-2018, 07:15 PM  
Sticky: Stop-down metering, why it is a problem, and how to make it work
Posted By stevebrot
Replies: 63
Views: 51,515
No, this is not another rant about the so-called "crippled mount". Instead, the intent is to provide a useful summary of why stop-down metering is often disappointing with modern dSLRs.

Stop-down metering

Stop-down TTL metering has a long history (see Pentax Spotmatic) and has long been considered the "Gold Standard" of TTL metering in that it measures the actual light at the taking aperture rather than an estimate based on a wide-open measurement. Even though all K-mount bodies support open-aperture metering, bodies having the so-called "crippled mount" (all Pentax dSLRs) limit this feature to lenses capable of automated aperture control by the body. In practice, this means lenses without an aperture ring or those with the "A" position on the aperture ring. Other K-mount lenses will still work using the aperture ring, but with in-camera metering limited to measurement with the lens stopped down.

K-mount auto-aperture actuation options include:
  • Maximum aperture only in modes other than M (default to Av)

  • Green button (instantaneous stop-down) in M mode to set shutter speed

  • EV scale stop-down using optical preview in M mode (menu option on some bodies) with shutter speed set using e-dial


Manual aperture (M42 and manual/preset aperture K-mount) options include:
  • Continuous metering in Av mode (all dial positions except M, X, and B)

  • Instantaneous metering using green button in M mode

  • EV scale using optical preview lever in M mode (menu option on some bodies) with shutter speed set using e-dial


Why it is a problem on many dSLRs
More properly, why is exposure with stop-down metering so often simply wrong?

My personal experience only goes back as far as the K10D and on that camera, stop-down metering simply sucked. Regardless of the method used, metered exposure was often 1 or more stops over or under-exposed. This was a puzzle since *ist D users at the time were happy with the feature on their cameras and stop-down metering was consistently good on Pentax film cameras. Much was made of the issue on this site and other places on the Web as users struggled to secure behavior similar to what they enjoyed shooting with K-mount film cameras when shooting with adapted M42 and non-A K-mount glass.

For example, the two graphs below show the meter variance (LV)* from expected** for two popular lenses using green button metering on the K10D equipped with the stock LF-80 focus screen. The X-axis is f-number.


The intended takeaway is:
  • Variance existed even at maximum aperture where the meter should have been seeing exactly the same light

  • Variance may be both positive and negative even with the same lens

  • The degree of error varies by both aperture and lens

Those two graphs are a mild example. I have lenses that metered as much as 2.5 stops from expected, but which provided properly exposed frames if set to the expected shutter speed aperture combination.
Question #1: "What does the meter see different than the sensor?"
Question #2: "What is different between a lens wide open with the aperture ring in the "A" position and the ring in the wide open position?"

Answer #1: The viewfinder optical system, specifically the focus screen
Answer #2: When the ring is off the "A" position, the body detects that it cannot control the taking aperture and has NO reference as to what it might be.
PDAF autofocus cameras all share a common fault in that light is diverted from the viewfinder to drive the AF sensor. To offset the resulting dim viewfinder, focus screens have been designed to optimize brightness. Two side-effects happen as a result:***
  • The light intensity viewed by the meter sensor is not representative of or even proportional to that which will strike the image sensor. How much it is off depends on the aperture size (rear pupil diameter to be precise) presented to the focus screen, not light intensity.

  • Ability to show the out-of-focus state is also compromised...apparent depth of field is increased down making manual focus difficult. This point is another discussion and will be ignored for the present.

The variance from expected metering is most likely due to the focus screen brightening. This hypothesis has been strengthened by user experience substituting screens from *ist D series bodies as well as results from non-brightened aftermarket screens. In short, variance changed depending on screen, with none of the aftermarket screens providing a clear improvement.
Conclusion? The camera applies a set of correction factors based on the known maximum aperture of the lens mounted when information is available from the contacts on the mount. Without correction factors, the meter is basically reading spurious light from an unknown fall-back position as far as exposure calculation. As a side note, this problem extends to other brands as well. Backward compatibility for many F-mount lenses on Nikon dSLRs depends on stop-down metering and their users were reporting similar issues.

Summary points run something like this:
  • Both accuracy and linearity of stop-down metering are potentially compromised by the optical path present on modern dSLRs

  • The problem is not easily solved by simply dialing in a little exposure compensation

  • The degree of inaccuracy depends on the lens used and aperture set with some lenses being badly effected and others much less so


Is this still a concern? If so, what can we do?

The problem was widely known and had been acknowledged by Hoya/Pentax prior to the K20D release. There was great disappointment when stop-down metering was not improved on that model. When the K-7 was released in 2009, one of the announced improvements was better accuracy and linearity for stop-down metering. Happily, there was a significant improvement that joyously welcomed by many of us using vintage lenses. Since that has been almost a decade ago, one would think that incremental improvements should have resulted in near perfection.

Sadly, that is only partially true. Before sitting down to write this piece, I mounted up an XR Rikenon 50/2 to my K-3. In M mode at f/5.6, both green button and EV scale metering resulted in at least a 1.5 stop overexposure. Other users are encouraged to add their comments and experiences, but my present understanding of optical viewfinder metering runs like this:
  • The initial fix on the K-7 was limited to M-mode. Av metering in other modes continued according to the old rules from the K10D/K20D.

  • I believe that situation from the K-7 extends to the present. When I took delivery of my K-3, I checked both methods against the K10D and found that Av numbers were similar with both cameras. K-3 M-mode metering is better than I remember from the K-7, but still far from perfect.

  • Green button and EV scale metering in M-mode are fully equivalent. This applies to both K-mount and M42 lenses.

My personal recommendations run like this:
  • Use M-mode with either green button or EV scale for viewfinder metering with K-mount lenses

  • Similarly, use M-mode with green button for M42 lenses. I almost never use the Av option at present.

  • Seriously consider carrying a hand-held meter and gray card when shooting with non-A lenses. The hassle is often much less than chimping and figuring, and chimping some more.

  • I have been experimenting with center-weighted metering TTL in Live View using green button in M-mode. Once the exposure is determined, I change back to viewfinder and shoot at will until either the light or the subject changes. The results are very predictable and accurate. Paradoxically, I have been getting better results with M42 lenses using green button in live view than with Av mode. Go figure, they should be the same.

I anticipate some useful comments from our very competent members. Thanks in advance :)


Steve

* LV = Light Value, an expression of measured subject luminance equivalent to EV at ISO 100

** LV was about 7 on an evenly lit white wall using natural daylight. Expected values were metered with the lens aperture ring on the "A" position. A positive variance indicates an underexposure situation.

*** Both can be seen directly through the viewfinder when using the optical DOF feature. The screen does not darken appreciably until stopped down somewhere
around f/4.5. Similarly, there is little change in DOF as the lens is stopped down at wider apertures.
Forum: Weekly Photo Challenges 11-05-2019, 07:02 PM  
Weekly Challenge #476 - "Minimalistic Imagery"
Posted By aaacb
Replies: 42
Views: 3,219
Forum: Weekly Photo Challenges 11-05-2019, 05:40 PM  
Weekly Challenge #476 - "Minimalistic Imagery"
Posted By bigoak
Replies: 42
Views: 3,219
take a load off
Forum: Post Your Photos! 11-05-2019, 07:06 PM  
Nature Yeh, I know - another red dragonfly!
Posted By Tonytee
Replies: 3
Views: 424
Just about my favorite insect in the whole wide world. I have never seen a red one of these before. Also, very interesting settings. Nice work. :)

TT
Forum: Pentax K-3 & K-3 II 11-05-2019, 03:20 PM  
why I won't buy a k3 (Warning: Satire Thread)
Posted By robtcorl
Replies: 103,007
Views: 4,833,200
Do you ever have to renew the plates on your televisions? :p
Forum: Photographic Industry and Professionals 02-20-2018, 04:56 AM  
What is Pentax doing?
Posted By Digitalis
Replies: 82
Views: 9,351
¯\_(ツ)_/¯
Forum: Photographic Industry and Professionals 02-19-2018, 11:53 PM  
What is Pentax doing?
Posted By pinholecam
Replies: 82
Views: 9,351
I think whatever they are doing, they are keeping the cards close to their chest.

Anyone's guess is as good as another's.
We all know the possibilities :
1. Slow down and wind down the business
2. Think over what to do with the camera lines (ie. mirrorless? 645? bigger/smaller lenses, etc).
3. Be the leading brand in IQ and the DSLR experience while others move to mirrorless.
4. Leapfrog the competition with more experimental stuff (eg. Theta; HP camera colaborations; etc)
5. Be a "boutique" maker like Leica -more expensive, really well built, expensive and niche to avoid mass market madness and race to the bottom

Of course if AFC is improved, it will be great.
If the DR was like 18 stops in one shot, that would be candy.
Video 8k, wow! - fantastic so long as I don't have to pay for it due to a faster chip/ pipeline since my video use is '0'.


Personally, I feel myself being removed from all these over the years.
Its come to a point where lenses are lenses and I have plenty of them to play with and get the effect I want.
Cameras are well past the point where I need more MP and even DR is rather moot as I either get it within 2-3 bracketed shots layer blended or not need the DR at all and just expose for the important stuff.

If Pentax closes, I'd be disappointed, but I'd probably get their last FF camera and that should last me years, then I move on to whatever that can take the lenses with an adapter.
The "invested in XXX brand" argument is no longer as relevant as it used to be to me.
I shoot multiple genres both with AF/MF and on poorer AF and I have never found that my photography has been limited because of the tech.
Yes, that includes the fastest most erratic moving athletes in the world (called kids :D );
My skills have carried thru from camera to camera be it AF/MF and that has been the most important part of getting photos.
Its just so easy to get lead away with all the tech talk (camera vs camera ) that we forget the reason we shoot.
For the the things we love/like/family/friends/beauty/etc...
Forum: Photographic Industry and Professionals 02-19-2018, 08:26 PM  
What is Pentax doing?
Posted By Poit
Replies: 82
Views: 9,351
I would like Pentax to be on a (semi) level playing field with others.

Why? Because it will attract more customers. More customers = more revenue. More revenue = more R & D. More R & D = better cameras for us Pentaxians.

Simple
Forum: Lens Clubs 05-08-2009, 03:14 AM  
The FA Limited Club
Posted By pcarfan
Replies: 11,825
Views: 2,138,450


100% crop

Forum: General Photography 01-13-2018, 07:30 AM  
Inside one of America's last pencil factories
Posted By monochrome
Replies: 15
Views: 1,826
The photographs evoke a lost society in which people were part of the fabric of production. We’ve thrown away the value - real money value - of their experience and skill in favor of silicon and algorithms, and we are poorer for it. My father and grandfather owned a printing and office supplies company - closed in the 1980 recession - so an article about pencils has a strange, poignant interest. Pencils (and tape and staples and paper clips and gummed pads of paper and typewriter ribbons - Typewriters!!) fascinate me.

I grew up in the printing plant and warehouse loft building and was taught by my father’s employees about work, accuracy, schedules, operations and given many little habits that are with me even today. My character and behavior were judged by the front office ladies - often harshly - with my father’s tacit encouragement. Now those lessons and judgements are given by Twitter and Facebook.

I keep and use mechanical film cameras and manual lenses specifically because they were assembled by people. I dislike the idea of throwing away the skill and labor and time embedded in these objects when a simple adjustment will keep their work useful as long as we have film.
Forum: Pentax K-1 & K-1 II 02-17-2018, 04:49 PM  
My Canon to Pentax experience: Why I love Pentax, but might still leave.
Posted By motorhead9999
Replies: 46
Views: 7,886
I've had my Pentax K1 now for about 5 months. I originally a Canon 6Dmk1, which was my first full frame camera. In general I was happy with Canon, but there certainly were things about my 6D I wasn't crazy about. After travelling to shoot the eclipse, and having a Canon 7D that I borrowed from a friend on a tripod angled at nearly 45 degrees, but not having a broken neck because of the nice angled swivel screen (an issue that I had suffered greatly with the 6D's lack of one), I decided that it was time to change that. Originally I had wanted to remain within Canon, but my other full frame option (the 5Dmk4) didn't have one either. I didn't have so much Canon glass that I'd take a horrendous loss, combined with the fact that the Black Friday deal I had gotten on my camera was so good that I'd basically break even selling the body meant that I wasn't locked into stay with Canon. I had originally drifted towards Sony, but after some horror stories about customer support with them, as well as some of the Star Eater issues (of which astro is one of my chief enjoyments when doing photography), I decided to stay away. So obviously Nikon was going to be the winner, especially after the announcement of the D850. After watching Tony and Chelsea Northrop's Pentax K1 review though, I became slightly sold on the camera from the brand that nobody I knew bought. I kept doing my research, and the camera certainly had enough points in it's favor. I took the plunge (rather nervously I might add, as I felt I was taking a large risk on the brand, given many of the criticisms I had read both on this forum and elsewhere). So here's where I stand 5 months out. I'll talk a bit about what I like, what I don't like, and my thoughts about remaining in the Pentax ecosystem.

Remember, I'm not a professional. I don't make a living through photography. It's a hobby for me, and I don't claim to be an expert at it. If I misstate something in this review, please tell me. I enjoy being educated.

So far, I have the following lenses: 15-30, 24-70, and 150-450.

Things I like:
The controls: In all seriousness, this is probably my favorite aspect of the camera. All of the buttons make sense, the layout is impeccable, and most importantly, the 3rd user selectable wheel! The fact that by changing that one extra button to ISO means that I've got independant controls over f stop, shutter speed AND ISO all within reach of my fingers when shooting is nothing short of miraculous. I did my first concert photography shoot recently, where the light settings are constantly changing, between almost too dark to see, and blown out, and the ability to keep my aperture and shutter speed fairly constant, but just notch down my iso for a quick moment, and then switch back was a blessing.

The build: It's built like a tank. Plan and simple. I haven't felt afraid of putting the thing on the ground, of using it at the beach, or out on trails. I've been rained on a few times, and the fact that I don't have to be paranoid of getting a water droplet on it certainly helps me feel more confident on going for a shot. The lenses, particularly the 150-450 are built like tanks as well, and the ergonomics and features are by and large comfortable. I certainly prefer using/dealing with the 150-450 over the 100-400 Canon (I don't remember the exact focal range but it's the white Canon telephoto) that I had borrowed for the eclipse.

The lenses, and lens selection: This is a double edged sword, so here's the first edge. People complain about the lens selection. Honestly, (and I'll talk about it later), given the lenses I have, it's not as big an issue as I initially thought it'd be. I haven't felt the need to get the 70-200 lens yet (for the time being, I can't say I've ever felt like I missed a shot because I didn't have something to cover the >70-149 range), but if I were to pick it up, I would be covered with great quality lenses from 15mm all the way up to 450mm (and 15-200 of that would be at a pretty fast aperture). That's nothing really to sneeze at, and really what else would you want? And as I mentioned here, and in the previous point, all the lenses have been of terrific image quality that I can't really say I'm unhappy with them, or that the trinity is lacking. So yeah...the lens situation isn't as bad as everyone makes it out to be

Image Quality: This goes without saying. The first time I took a water shot with this camera, I was in awe of how good the photos were, especially compared to my 6D. I can't tell you how many times I've just been blown away by how crisp this camera can get. I really don't know what else to say here. When Tony and Chelsea's review called it "the greatest landscape camera ever", they weren't lying.

The body price: It's roughly half the price of a D850 or a7r3, and a grand cheaper than a 5dMk4. 'Nuff said.

The tilt screen: While I don't go around dangling the camera by the tilt screen, I do feel it's a lot more secure and robust than say the Canon or Nikon style. But really, the screen is nice and clear (albeit sometimes hard to see in sunlight), and it certainly encourages me to get my camera down nice and low sometimes to get a shot that I wouldn't have thought, or tried to get other times.

"A good enough sports camera": Does this thing have the fire rate that a D500 has? No. But you know what? I have to say that the K1 has performed far better under fast motion conditions than I really ever hoped it would. I've always had poor luck at concerts, but this camera certainly held up to performers moving around on stage and doing unpredictable things. I also did an engagement shoot with it, and it worked just fine for people moving around naturally.

Things I'm "meh" on:
The autofocus: I really didn't want to put this in the "things I don't like" section, because really, I don't think it's AS bad as some people make it out to be. Yes, it can absolutely be better, and we can all only hope that we get Nikon or Sony level qualities of autofocusing one day. In the wildlife photography I've done, I've found the autofocus grabs things reasonably well, and quick to get the shot I want. But yeah...when I've got a heron 6 feet in front of me, and 3 smallish reed plants in front of it, and all the autofocus wants to do is blur the heron to get the reeds in focus can be frustrating. I'm still learning the ins and outs of focus points and selecting them, so there's certainly room for ME to grow in this, and may not be entirely the camera's fault, but I've had enough times, and there's enough community complaints out there for me to be comfortable with saying there's room for the camera to grow.

Things I don't like:
The lens selection: Here's the other edge of that blade I promised. Yes, I have 4 glorious modern lenses from the 15-450 range to choose from from Pentax. But beyond that, there's not a lot out there. Yes, I understand I have the entire 30 years or so of Pentax legacy lenses to choose from, but honestly, that's not always for everyone. Whether it be because of issues with some of those legacy lenses on the K1,or that I/we like having the latest and greatest technology, or the fact that I don't want to have to deal with garage sales, or ebay to try out some really old lens, beyond those 4 lenses, there's not a lot out there for the K1. We basically lose Tamron as a manufacturer, due to their basically being Pentax's manufacturer, Sigma's support and options for K-mount is minimal to say the least, and even Rokinon doesn't have a large selection for us. If we want things like fisheyes, or ultra fast 1.4 lenses (outside of the Sigma Art 35mm, which I think is the one lens Sigma DOES carry for k-mount), the support is simply not out there. And when you want those lenses, it's frustrating that you can't get them. As I stated in my other half of this argument, the fact that Pentax's lineup does cover so much of the usual range with good quality makes this issue not as painful as people online make seem, but when something's missing, it really affects you.

The battery grip: I was super excited to buy this thing. And in all honesty, I ended up returning it. While it was nice to have the extra shutter button, the fact that the grip design basically made it so that one battery was no longer accessible, and then you only had a single battery slot in the grip itself made it a disappointment for me. In the end, I felt it was easier simply just to keep a single spare battery if that was the case. Yes, I miss having that extra oriented shutter button, but it wasn't worth it. Another reason the grip ended up being the bane of my existence was....

Lack of third party support: To continue from my point above, there is no available L-bracket available for the K1 with battery grip. I can (and did) get one for the base K1 from RRS (which I'm extremely happy with!) and some others, but not with the battery grip. You can get one for Canon w/ a battery grip. You can get one for Nikon w/ a battery grip. But not for Pentax. And in general, that's the story for Pentax items. Unless it's offered for sale by the parent company, we generally can't buy it, and our marketshare is so small that nobody wants to make anything for us. You can probably lump in some of my complaints on the Sigma/Tamron lens support here too. We are simply an afterthought to the rest of the market. And heaven help any of us if we ever need to get a Pentax item in a pinch from a brick and mortar store. Much like my comment earlier, its not as big a deal as I'm making it out to be, but when you want something as simple as an L-bracket, and you have to either compromise with what you want, or find some really burdensome workaround, it can get pretty maddening.

And my last dislike, and combined with why I might leave Pentax:
An unknown and shaky future: When the lack of support and marketshare, combined with frequent questions about the longterm future or support of the product and system by the parent company are so hugely out there, it constantly gives me second thoughts about staying around the Pentax line. Let's face it. If it becomes known that Pentax will either be discontinued, or "reimainged" or whatever it might be, we all stand to lose a ton on our gear. So you either get out now, and eat your loss, or simply use it till it dies, lose everything, and until then always have that nagging fear that tomorrow might be the day you have to buy a whole new camera system.

At this point, I'm far more invested in Pentax gear than I ever was when I was with Canon. I'd love to simply keep my lenses and change the body out with a new model every 4 years or so. I just don't get that comfort level with Pentax though. And while it's still an unconfirmed rumor, the rumored K1v2 leaked specs are not reassuring at all in terms of the roadmap this company seems to have. I listed a lot to like about the camera and the system earlier. As much as I do though, for all intents and purposes, Nikon and Canon are equally good systems. Each have their pros and cons of course, but still, at least those two you can certainly see lasting well into the future. If I can get more or less the same quality shots out of a D850 as my K1, but get into a much more stable and widely available ecosystem (not to mention still getting good value on my current gear) that I don't have to constantly fear is going to abandon me, then why not do it now rather than later?

It's not like I want to switch mind you. If there's one thing my K1 has done for me, is it's been a damn good enough camera that it makes me want to go out and take pictures, and more importantly, experiment with different things that I never would have thought to do. That says something, and in the end, isn't that what all of us want? To not think about the gear, and just simply think about what we really want to do, which is take gorgeous photos.

I'm not jumping ship yet, just to be clear. It's something I think about though. But in the meantime, I'm going to keep taking photos.


Forum: Pentax SLR Lens Discussion 01-09-2018, 05:26 PM  
If Pentax made a HD DA 28mm f/2.8 Limited......
Posted By mikesbike
Replies: 105
Views: 7,283
The FA 28mm f/2.8 (or "F") is a very good lens. I've had one since the film-only days. It is light-weight and compact. It is quite sharp even wide open. And it is of course usable for APS-C as well as FF. But to get a fast lens in a prime of this FL, the Sigma 28mm f/1.8 EX DG shows what it takes in terms of size and weight to achieve it. I have a similar Sigma lens, but instead chose the 24mm f/1.8 because it is wider-angle, and as it has turned out, still offers some wide angle when used on my APS-C bodies, and is therefore more versatile. I don't mind the extra size and weight. To obtain a greater aperture, greater size and weight is always an expected price one pays, in addition to the added cost.
Forum: Pentax SLR Lens Discussion 01-07-2018, 09:35 PM  
If Pentax made a HD DA 28mm f/2.8 Limited......
Posted By pres589
Replies: 105
Views: 7,283
Yeah, this is why I keep talking about a 26mm f2.4 plastic built prime. For folks that want something a bit more wide than the 31, longer than the 21, and light/cheap.

I have no reason to think it will ever be made.
Forum: Pentax K-1 & K-1 II 02-22-2017, 04:34 PM  
Using Leica-M Lenses on a Pentax K-1
Posted By Digitalis
Replies: 21
Views: 12,582
The flange distance on Leica lenses is almost half the distance of the K mount 45.46mm flange. Without additional optics in the adapter to compensate for this, infinity focus will be impossible to achieve*. Leica M lenses do not focus closely due to the inherent inaccuracies of the RF mechanism,so close focusing ability is reduced and thus, the focusing throw of** Leica M lenses is reduced drastically compared to common SLR lenses.

If you really want to use Leica glass on K mount your best option would be the Leica R series lenses. These are relatively straight forward to adapt to K mount, and as they are SLR lenses they offer a wider focus throw than their smaller M counterparts.

* The seller mentions this caveat.
** macro lenses do exist for Leica M cameras, however magnification is limited to 1:2. For this application It is far easier to use an SLR - at least you can see the focus errors coming.
Forum: Post Your Photos! 11-02-2017, 05:27 PM  
Not Work-Safe Johannsdottir (film + digital)
Posted By alan_smithee_photos
Replies: 11
Views: 622
Wow, has it really been almost a year since I last posted photos? Well, it's not for lack of shooting. :)

A few shots below from my shoot with Johannsdottir, an Icelandic model visiting the states.

Digital are processed with Mastin Labs FujiPro 400H presets.

K-1, Voigtlander Nokton 58mm 1.4 SL II

Rolleiflex 3.5, Portra 400

K-1, FA 43mm 1.9 (shot through a prism, no other trickery)





(no prism)



Rolleiflex 3.5, Portra 400







Fuji Acros 100




Forum: Post Your Photos! 11-03-2017, 10:20 AM  
Not Work-Safe Johannsdottir (film + digital)
Posted By RoxnDox
Replies: 11
Views: 622
Johann certainly has a beautiful dottir!

I couldn't pick a favorite, they're all gorgeous shots with posing, lighting, curves (hers and the light) all wonderful.

Jim
Forum: General Photography 09-08-2016, 01:07 AM  
Stanford Professor puts his entire Digital Photography Course online For Free
Posted By BigMackCam
Replies: 11
Views: 2,050
That's a really good idea. It would be an incentive to do the whole course within a reasonable time - I'm terrible for dragging my heels on things like this :lol:
Forum: General Photography 09-06-2016, 05:13 PM  
Stanford Professor puts his entire Digital Photography Course online For Free
Posted By monochrome
Replies: 11
Views: 2,050
I just had a mind flash that a group of us could take the course together, on some agreeable schedule, upload our photos somewhere and comment on / collectively critique them.

A Social Group like the 'Single In' Group might work.
Forum: General Photography 09-06-2016, 12:00 PM  
Stanford Professor puts his entire Digital Photography Course online For Free
Posted By monochrome
Replies: 11
Views: 2,050
Here's an article from DIY Photography that includes several different links to access the multiple hours of video content, plus several apps for technical calculations.

EDIT: This appears to be a highly technical course, not just see the light, compose and expose.
Forum: General Photography 09-06-2016, 02:30 PM  
Free vintage photography books for Kindle - worth a look
Posted By BigMackCam
Replies: 4
Views: 1,116
Forum: Pentax DSLR Discussion 09-06-2016, 06:22 AM  
Question about Pentax as a brand
Posted By Kunzite
Replies: 73
Views: 8,278
Indeed - pros are using mostly Canon and Nikon because those brands have the expensive speed monsters like the D5 and 1Dx Mark II - and the expensive lenses to match. Unless we're talking about those pros who are after the best image quality, then it's not Canon or Nikon - but medium format (Pentax is a player here).

Agreed on Shake Reduction for panning; I'm assuming here Razvan would get an older model. I'm still not fully familiar with the K-1's SR... maybe it's not a problem anymore? In any case, this is one upside of the in-body SR: it gets upgraded each time you change your camera. For all your lenses ;)

As for cold:














You Tube



Forum: Pentax DSLR Discussion 09-06-2016, 12:40 AM  
Question about Pentax as a brand
Posted By Kunzite
Replies: 73
Views: 8,278
I thought it might be so.
Well, we can get together, have a drink or something - and I can show you a K-1 (if you're curious), K-5IIs, few DA Limiteds; or if you have specific requests, we could try to find a solution.

I'm also thinking of having another Pentaxian meeting this autumn.
Forum: Pentax DSLR Discussion 09-05-2016, 10:19 AM  
Question about Pentax as a brand
Posted By AggieDad
Replies: 73
Views: 8,278
Welcome.

The responses you have received are why I love this forum.

You have received a great deal of accurate and objective information and very little hyperbole and defensiveness. The people who have responded have given you fair and honest answers, freely discussing the positives and negatives of the brand, and given you, what I feel, is an accurate picture of Pentax cameras.

I won't even try to give you any thoughts about which camera is best for you - you have read plenty about that - and it is your decision anyway. I will suggest that you to spend some time reading through our forum as well as the reviews and articles sections. I believe these will be very telling and informative for you. This will give you the opportunity to see what Pentax people say to other Pentax people. I especially urge you to look at this LINK which demonstrates the effectiveness of the Pentax weather sealing.

Whatever you decide, I wish you the best and hope your choice works well for you.
Forum: Pentax DSLR Discussion 09-04-2016, 05:46 PM  
Question about Pentax as a brand
Posted By CarlJF
Replies: 73
Views: 8,278
It's more than nice to have! And if you don't want to use it, you can just turn it off... As to why Fuji hasn't choose to use IBIS, their talk about lo IQ is BS... Because Fuji isn't able to dit doesn't mean it's not possible to fo it. Pentax, but also Sony and Olympus use IBIS and their IQ are not exactly second rate.






For one thing, and as you have noted, the pro with Canon don't use the same gear as the one you're looking at. And there's a world in features, built quality and general performance between a high end pro model (and pro lenses) and and entry level one with consumer-level lenses. With a budget of 1000$, you're far away from what a pro uses (often more than 10 000$ in gear). The pro choose Canon because, mostly, they can find (buy or rent) almost any lens needed for a job, even if a highly specialized one is needed. For example, if you're on assignement to shoot a documentary on lions in Africa, you may absolutely need this 10 000$ Canon telephoto lens. But the reason a pro choose this is probably not really relevant if you're a hobbyist on a budget... And the last reason is the Canon Professional Service (aka CPS). If you're a pro, it is really great to know that you can get your gear repaired in a matter of hours or get a loaner to do your job. If you're not a pro, you can't use this service and, again, the reason why a pro choose Canon has nothing to do with the reality of the amateur photgrapher on a budget... This big advantage for a professional isn't one for an amateur since it doesn't have access to this pro service. It's somewhat like saying that because pro car drivers drive Ferrari and Mercedes, these should be the best buy for the everyday commuter on a budget.... The pros needs and goals are quite different than the ones of the non pros.





I would recommend a K-S2 or K-70. If you really want the best IQ, K-70 and its high resolution mode is unmatched at this price point.


What keep me with Pentax is quite simple: it offers me what I want at a decent price. More to the point, with Canon and Nikon I would have to buy at least a 80D or a D7xxx just to get dual wheel control. Which is for me a basic feature needed on any serious camera. And IBIS is just great. Having all lenses stabilized is really useful. And not asking myself everytime I buy a lens if I take the stabilised version or the cheaper non stabilsed one is something I really like...


What annoys me is the lack of cheap flash and radio flash trigger. Although many people pointed the AF as a downside, I must say that for me it hasn't been a problem and has proved itself good enough in everyday use. But I'm not doing sports or action photography...
Forum: Pentax DSLR Discussion 09-04-2016, 05:25 PM  
Question about Pentax as a brand
Posted By interested_observer
Replies: 73
Views: 8,278
I figure that I might as well add a few comments....
  • Autofocus - Canon and Nikon undoubtedly have the best fastest autofocus and tracking. Pentax's autofocus is a tad bit slower, but it does lock accurately. The autofocus has been under constant improvement for quite a while. In its latest version in the K1 - it's said to lock very fast, and it tracking has been criticized as not as good as with C&N. However, there are a number of threads showing the AF locking on speeding dirt bikes just fine. The reviewers always have to find something to harshly criticize with Pentax. Here is an article from a German magazine that did an analysis of Pentax's AF system. The bottom line was that it was a bit slower, but more accurate in terms of lock. Also, Pentax has two types of AF - screw drive and AF motors. All Pentax bodies support both systems. Also, Pentax has two types of AF lock - phase detection and contrast detection and all CMOS sensor bodies support both. Phase detection is done via a separate sensor in the body and is done via the viewfinder, while Contrast Detection is done on the sensor and is used with liveview.

  • Shake Reduction - SR is one of the items that drew me to stay with Pentax when switching to digital 10 years ago. I have gone from the K100D, K20, K5 and now with the K5IIs, there has been no problems - it just works and works well. It works on all the lenses. There have been really no SR problems reported over the years. If you don't want it - just turn it off. Any camera brand is going to setup the discussion in terms that what they offer or have is the best. Fuji is unable to fit image stabilization into their body. Sony, Olympus and Pentax have it and it is well proven.

  • Image Quality - To be honest, everyone's image quality is excellent. You really have to take a technical approach and start splitting hairs, but there are differences. Canon produces their own sensors. They do a good job, but they lag behind in dynamic range. This makes a large difference in the details within shadows. That is born out and shown in the DXO measurements. Nikon uses Sony sensors as does Pentax. In models where both Nikon and Pentax use the same sensor (Nikon D7000 Pentax K5, Nikon D800/D810 and Pentax K1), Pentax has shown that they have been able to squeeze additional performance out of the sensor at a lower level of noise. Here is a Noise DB site. Just compare the Pentax K1 to the Nikon D810 - same sensor. Pentax has half the noise. Pentax has also pioneered super-resolution along with Olympus. Pentax uses pixel shifting to achieve a level of super resolution with their K3II and K1. The second link is a good review of pixel shifting and the results you can achieve with it. That is where the claim of "second to none" comes from. But, take a look for yourself - use the third link to compare like images across various camera bodies. Let your own eyes decide.

  • Modes, capabilities and functionalities - Pentax includes a lot more capabilities in to all of their models than what Canon does. Both Canon and Nikon makes you move up in their lines to get additional capabilities. For the most part Pentax does not do this - at least to the extreme level that C&N does it.

  • Professionals - Ok, yes there are professionals shooting Pentax - but not to the extent that you will find in C&N. There are professional photographers right here on the Forum. Canon owns about 50% of the camera market and Nikon owns something over 30%. Professionals tend to migrate where they are supported. Canon has a professional service department that will lend out and repair on a couple days notice. Pentax really does not have a professional support organization to compare. Also, you can get Canon or Nikon equipment just about anywhere. Pentax not so much other than over the web / mail order. That is what is going to drive professional use along with lenses. Canon has the largest selection of lenses bar none, followed by Nikon. Canon and Nikon has the best flash system bar none along with tethering and tethering support. Pentax covers all the major bases, but not to the extent of the other two. Professional photographers choose the other C&N based on support and selection - just not ONLY on image quality. Another aspect with pros is a full frame sensor. Pentax has delivered there with the K1 earlier this year. That is the one area that the professional shooters gravitated towards. Pentax has the 645 Medium Format, that attracted a lot of attention and use, but the full frame is where the professional photographer needs are.

  • Menu Systems - This in my opinion is pretty much personal preference based on what you are used to. Canon shooters hate Pentax's menu system - because they are different. I have read that since pros prefer Canon, that makes Pentax's menus garbage. Personally, I somewhat disagree. Once you are use to the menus, they are easy to use, and on the K5, K3, K1 camera systems - the control buttons relieve the use of the menus a great deal. Pentax menu systems are all very similar. What varies across models are the number of direct user control buttons that let you bypass the menus for the vast majority of shooting.

_________________

I too am on a fixed budget. I just retired last Friday - 2 days ago now. I tend to buy the model that is being phased out, and skip at least one generation or perhaps two. Buying at the end of the model run, reduces the price a great deal. I shoot landscapes, cityscapes, architecture, night and astro. Ambient low level lighting - darkness, with long exposures. The tripod with a good head is my friend. I use a K5IIs and have not out grown it in the slightest. A K1 would be nice for the astro work since that would provide at least one extra stop in light gathering ability (larger sensor), among a few other things - like super resolution and the tilt screen. However right now I have skipped over the K3 and K3II. They offer additional capabilities - more resolution and super resolution. I don't know what I will do going forward, however right now I am not compelled to do anything other than go out and shoot with what I have.

Some additional thoughts....
  • Philosophy - Both Canon and Nikon are marketing machines. For whatever reason, Pentax cares little about marketing and tends to go the technical / engineering route. For example, let's take images right out of the camera. Let's start with RAW images. The reviewers, will say - wow! they are so sharp. Well Canon and Nikon pre-cook their RAW images a bit with some extra processing in the camera (they just don't tell you) - especially sharpening, so that they get that reaction from the reviewers. Thus, C&N are better image processors? better sensors? better images? Pentax does very little of that, since they want to preserve and deliver the most image detail possible to the photographer. By sharpening too early in the processing flow, you destroy some of the information (sharpening is the last step you want to do in processing). Same thing with the JPGs. Just about everyone else has much more processing in their JPG engines than Pentax. So out of the camera they look great. Pentax does the minimum in order to preserve detail. The photographer can process to taste and produce better output with better detail.

:cool:
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