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Forum: Pentax News and Rumors 5 Hours Ago  
Visiting Photokina what I learned.
Posted By photoptimist
Replies: 75
Views: 5,451
Quite true!

Yet in this case, it may the planet Earth (and distance to it's star) and physics of this universe that are the limiting agent. The number of photons per second per square millimeter on that squirrel may be too low to get a short-duration, low-noise sample. Modern cameras really are reaching the limit of what is possible given the typical ambient light levels of photography.
Forum: Ricoh GR 15 Hours Ago  
Ricoh GR or GRII Teleconverter
Posted By photoptimist
Replies: 2
Views: 208
Nice results!

These kinds of convertors can be fun.

I've got a Canon WC-DC58 -- a 0.8X convertor with a 58mm thread. It does a decent job on 28mm lenses on APS-C to create 22.4 mm lens of the same f-stop. On FF with a 28 mm lens, the converter vignettes and has horrible corners.

There's also a Canon TC-DC58 -- a 1.5X convertor with a 58mm thread. I've not gotten much chance to play with this one.
Forum: Pentax SLR Lens Discussion 17 Hours Ago  
What are the chances that the DA* 11-18mm will be FF compatible?
Posted By photoptimist
Replies: 24
Views: 913
Well, then you'll also be cheesed with Canon, Nikon, Sony, Leica, Sigma, and Tamron. All the major makers have a line of APS-C lenses that go on APS-C bodies that use an FF-mount.

As others have noted, a lens restricted to an APS-C image circle can be smaller, lighter, and cheaper for a given level of lens performance.
Forum: General Photography 1 Day Ago  
The eye of the beholder.
Posted By photoptimist
Replies: 44
Views: 827
So that's one of them He-brides, eh?
Forum: General Photography 1 Day Ago  
The eye of the beholder.
Posted By photoptimist
Replies: 44
Views: 827
Yes, beauty is in the eye of the beholder ...

...and stinging pain is in the palm of the beeholder. (Spoken from experience!)
Forum: Pentax News and Rumors 1 Day Ago  
D-FA* 85mm f1.4 also coming
Posted By photoptimist
Replies: 1,806
Views: 153,306
The FF debate is really a version of Goldilocks and the Three (or Six) Sensor Formats.

The range of ILC sensor sizes from 1" to micro 4/3rds to APS-C to full 35 mm to crop 645 to full 645 etc. etc. create a bathtub curve in trade-offs. Most photographers might agree that a 1" sensor may be "too small" to get clean images. And most photographers might agree that a full 645 sensor may be "too large" to carry. But the middle sweet spot depends on each photographer's tastes -- whether lighter weight and reach is sweeter than low noise and shallow DoF.

Personally, I love the K-1 but then I'm more of a wide-to-normal FoV photographer who doesn't mind carrying 7 kg of camera and lenses on an all-day hike. But I can see why others would prefer tiny lenses on a tiny body with a tiny sensor.
Forum: Non-Pentax Cameras: Canon, Nikon, etc. 1 Day Ago  
Sony just updated their Sensor database
Posted By photoptimist
Replies: 7
Views: 287
Weird! Sony's one FF sensor option sucks. 24 MPix seems like a big step backward on resolution. The 19 fps speed would help with pixel shift (grabbing all four frames within a quarter second) but otherwise offers almost no advantage to most of kinds of still photography (e.g., landscape, product, architecture, astro) that Pentax excels at.

Time to look for another sensor maker!
Forum: Pentax Camera and Field Accessories 2 Days Ago  
The importance of a hood with a ND Filter or CPL?
Posted By photoptimist
Replies: 12
Views: 532
Flare is caused by the relative brightness of the main subject of the scene and any light sources in the frame or out of the frame. The sun and sky may be incredibly bright relative to the dark waterfall subject matter. Even a landscape lit by a full moon will flare as bad as a sunlit scene if the moon is shining into an unhooded lens.

Although a CPL or ND reduces the absolute brightness of the scene, it does not change the relative brightness. If anything adding a CPL or ND can worsen flare because it adds another optical element, two more dirt-encrusted optical surface layers, and another reflective surface to the optical system.

That said, if the sun is behind the camera and there's very little sky visible between near the frame to overhead, then a hood may not be needed.
Forum: Pentax News and Rumors 2 Days Ago  
Yay! Ricoh Imaging will announce a new camera this month or next month! (Nokishita)
Posted By photoptimist
Replies: 119
Views: 7,309
Didn't the K-5, K-50, and K-500 all share the same 16 MPix sensor?

I'd think that differences in body size, number of knobs & buttons, stilty-tilty screen versus fixed screen, two or one card slot, accelerator chip versus not, GPS versus not, pixelshift versus not, etc. provide a good basis for differentiating the classes.

In general, companies profit from a multi-class product system based on a shared technology platform by getting a higher margin on the high-end version but using the volume created by the low-end version to get better economies of scale. In essence, the flagship model pays for the R&D and the featherweight model keep the factory humming.
Forum: Troubleshooting and Beginner Help 2 Days Ago  
Looking for an upgrade from K-5, shooting macro only
Posted By photoptimist
Replies: 8
Views: 427
I can't comment on the video autofocus side but it is worth noting that an APS-C sensor is often better suited for macro than an FF sensor.

Unless you use the K-1 in crop-mode, you'll need to increase the magnification of the optics by a factor of 1.5X to get the same relative size of the object in the frame. That may mean adding extension tubes or a teleconvertor to the system.

Also are you sure that the softness of the image isn't being caused by diffraction? Closing down the aperture to get sufficient depth of field for macro often means giving up some sharpness in the focused parts of the image.
Forum: Pentax News and Rumors 2 Days Ago  
Yay! Ricoh Imaging will announce a new camera this month or next month! (Nokishita)
Posted By photoptimist
Replies: 119
Views: 7,309
I agree with the others that these are two FF DSLRs. It's "two classes" not "two formats." Back when Pentax only sold APS-C cameras, they often offered two or three classes such as the K-5, K-50, and K-500.

Now they are focusing on FF. That seems to suggest they might offer a high-end flagship FF plus a lower-end featherweight FF.
Forum: Pentax Medium Format 2 Days Ago  
Post your medium format photos!
Posted By photoptimist
Replies: 12,634
Views: 2,063,621
Absolutely! A well-designed demosaicing algorithm will estimate the full-resolution luminance pattern implied by pixel-to-pixel variations in all three color bands to fill-in the missing patterns in each color band.

But if the photo is taken with a strong red filter on the lens, then there will be very little signal and detail in the green and blue pixel channels and little ability to estimate the red-channel details that fell on green and blue pixels.

Thus, it's probably better to shoot in full color with no filter and then post-process with the channel mixer to convert the RGB image into a color-filtered monochrome. The only exception is that channel mixing cannot exactly replicate all the spectral effects of a color filter on the lens. For example, a picture taken through an orange filter might be subtly different from a unfiltered color image mixed in post to simulate an orange filter. A true orange glass filter might provide stronger green versus yellow contrast than the unfiltered+post-processing can version offers.

Post-processing of the unfiltered RGB image might be good enough to create the desired effect. Yet some photographers might seek a truer color filtration that only a color filter can provide.

Note: for those who have (and can use) pixelshift, the results with a color filter will be at full resolution.
Forum: Pentax Camera and Field Accessories 2 Days Ago  
The importance of a hood with a ND Filter or CPL?
Posted By photoptimist
Replies: 12
Views: 532
Overall, hoods are important even with a CPL and ND filter to prevent flare. Sometimes hoods don't do much if the lighting is 100% from behind the lens (e.g., on-camera-flash in dark interiors). But if the sun, room lights, or flash set-up is in front of the lens, then a good petal hood or rectangular hood can prevent very bright stray light from entering the optics (filter + lens) and fogging or flaring.

Unless you use a lenscap, I would not put a hoodless lens with a filter in a bag. Dirt and grease in the bag will get on the filter surface and all your pictures will be taken looking through the mess.

Lens-filter-hood is probably the way to go but you might need to use the step-up ring that you mentioned and a larger hood to prevent vignetting especially on the 35.

Lens-hood-filter would require a lens cap on the filter. Also, any light gaps between the hood and filter could cause flare from light entering the hood-filter gap, bouncing off the interior surface of the filter and entering the lens.
Forum: Photographic Technique 3 Days Ago  
Identifying a couple of odd filter discs
Posted By photoptimist
Replies: 5
Views: 309
Might they be IR-pass (visible-block) and UV-pass (visible-block) filters? Those would be useful for pictures with a camera with a full spectrum conversion.

(P.S. If you are measuring the attenuation of very dark filters, make sure you cover the eyepeice to get an accurate reading.)
Forum: Pentax Medium Format 3 Days Ago  
Post your medium format photos!
Posted By photoptimist
Replies: 12,634
Views: 2,063,621
A strong red (or blue) filter kills the resolution of any Bayer filter digital camera. It turns the 40 MpIx RGB sensor of the 645D into a 10 MPix monochrome sensor. (Green filters only kill about half the pixels)
Forum: General Photography 3 Days Ago  
What's the mirrorless winner - need your help please!
Posted By photoptimist
Replies: 29
Views: 1,042
Personally, I'd avoid crystal ball analysis entirely because the world is now changing too fast to predict the which camera makers will be around in 5 or 10 years.

Any of the makers could fall by the wayside in the shifting sands of consumer fads, a corporate restructuring, an accounting scandal, a bad economic downturn, or at the hands of a new competitor that's not even on today's list of options. Even the strongest can die or become marginalized has beens. In 2006, who would have bet that Nokia or Blackberry would lose so badly to a computer maker (Apple) or a search engine company (Google/Android)?

Moreover, there's no guarantee that the winning maker won't obsolete any of their systems. You can't really buy "Sony" or "Canon," only specific Sony or Canon systems that even more likely to disappear over the years than the maker. And as even the lenses become more electronic and software-based, the chance that today's bodies and lenses become incompatible with tomorrow's bodies and lenses grows. The optics of a lens may be forever, but the firmware can be obsoleted pretty quickly.

For the most part, the core technologies of digital cameras have matured to the point that any decent 2018 model camera will remain performance-competitive for a long time. The only exception might be high-end video where high-end 4k and new 8k is still developing.

Instead of worrying about investing for the future's winners, buy the system that has everything you need right now.
Forum: Digital Processing, Software, and Printing 4 Days Ago  
A "dedicated" computer?
Posted By photoptimist
Replies: 14
Views: 580
Have you considered upgrading the disk in your MacBook Pro? You can replace the current internal drive with a much larger SSD -- maybe up to 2 TB (see SSDs (Solid-State Drives) Designed for the MacBook Pro for details). Plus, many upgrade kits come with a little enclosure that converts your old internal drive to an external drive. That can be really handy for either additional storage or you just keep the old drive as a bootable backup with all your files. If the thought of doing the required computer surgery scares you, then see if there's a local Mac repair shop that will do the install for you.

Another "Apple solution" for storage is to get a Time Capsule. These devices sit on your network, can provide storage for Time Machine backups of your computers. But you can also just use them as network drive for shared external files. Time Capsules can also be upgraded with larger disks (I've got 6 TB drives in mine). The only disadvantage is that accessing files over the network, even on a wired gigabit ethernet cable is slower than using a USB-C external drive.
Forum: Flashes, Lighting, and Studio 4 Days Ago  
How to compare Flash Power (against others)?
Posted By photoptimist
Replies: 18
Views: 410
If worth noting that the guide number is a non-linear value -- power goes with the square of the guide number. Based on the numbers people have found, the Cactus RF60x puts out double the light (1 stop) of the Metz M400 flash. And the numbers people have found seem to imply that HSS for 1/500 shutter speed is maybe 1/8 the light of a normal flash (3 stops).

Thus, you can simulate the Metz M400 flash HSS @ 1/500 second shutter speed with the Cactus RF60x fired normally at 1/16th power. And if you want to simulate rapid cycling see if the Cactus RF60x @ 1/64 is enough light.

Overall, HSS requires a lot of power to get a fast shutter speed.
Forum: Pentax SLR Lens Discussion 4 Days Ago  
Sigma 17-50mm F2.8 EX DC FLARE PROBLEM
Posted By photoptimist
Replies: 30
Views: 800
In all three cases the sun is shining toward the lens and camera. It's worth noting that the sun is about 100,000 times brighter than the sunlit ground and potentially 10 million times brighter subjects in deep shade. Even the best lens coatings can't prevent all flare.

The photographer might think they are in the shade, but even the smallest sun dapple directly striking the front element of the lens will create flare. In such conditions, the lens hood is very helpful although sometimes a judiciously placed hand or dark piece of paper can block the sun.

The other solution is to make sure the sun is high enough in the sky, far enough to the side, or is behind the camera so that absolutely no sunlight strikes the front element.
Forum: Pentax News and Rumors 4 Days Ago  
K3ii replacement
Posted By photoptimist
Replies: 2,083
Views: 131,029
Exactly! There's almost nothing in a DSLR's AF system that is off-the-shelf: the optics, aperture mask, and PDAF sensor are all custom designed.

Rudimentary AF software could be created by any decent engineering student but it would be slow, not very accurate, and likely to be confused by complex scenes. Class-leading AF software that tracks moving objects against a moving background is orders of magnitude harder. And any AF involving tracking requires coordination with the software running the electromechanical controls of the lens motor system with both a feedback loop (to check focus) and a feedforward loop (to predict how Af changes are changing the AF systems). In tracking scenarios: the scene is moving, the lens motor is moving, and the sensor is getting new data all at the same time. The software needs to be written to compensate/predict for the fact that the system is using old data at every instant in time and trying to predict how the last command to the lens will affect the next sample of data in the context of an estimated mathematical of subject motion. It requires some really heavy math in signal processing and control theory to get this right.
Forum: Pentax SLR Lens Discussion 4 Days Ago  
Sigma 17-50mm F2.8 EX DC FLARE PROBLEM
Posted By photoptimist
Replies: 30
Views: 800
A few ideas:

Step 1: Take shots with and without the CPL to see if the filter is to blame

Step 2: Take shots with and without the lens hood on to see if that helps.

Step 3: Inspect the lens with a flashlight for fogging, fungus, and heavy dust.

Step 4: (if needed) Change how you shoot to avoid bright light sources in the frame.

Good luck.
Forum: General Photography 5 Days Ago  
10,000th post - and a BIG "Thank You" to everyone here!
Posted By photoptimist
Replies: 30
Views: 898
Congrats on reaching the top of the big 10K-Mount(ain) of posts. ;)

Thank you for all your work herding the fractious cats that prowl the forum. You help make this little corner of interwebs one of the nicer spots to visit, make friends, and converse about cameras, lens, life, and everything.
Forum: Pentax News and Rumors 5 Days Ago  
K3ii replacement
Posted By photoptimist
Replies: 2,083
Views: 131,029
Hmm... Replicating the decades of R&D and millions of dollars that Canikon have put into fast class-leading AF would hardly be a minor investment. Faster wifi, faster USB, and a deeper buffer all require more expensive chips and more battery power.

As much as I'd love all these updates, too, most are neither minor nor cheap.
Forum: Pentax News and Rumors 6 Days Ago  
Visiting Photokina what I learned.
Posted By photoptimist
Replies: 75
Views: 5,451
An established communication protocol, lens mount, flange distance does not help Pentax engineers much at all. Anyone can quickly specify these things on the back of a napkin. The hard part is designing new camera bodies, lenses, and accessories that actually adhere to the standard whilst delivering competitive performance. And that can actually be hard in an alliance due to interoperability requirements. If the members interpret the standard in slightly different ways, a Sigma lens might have trouble on a Pentax body with both sides pointing fingers at each other.

Joining an alliance is a very tricky double gamble for Pentax. First, it's a gamble that consumers will flock to the alliance's products. That implies that Pentax would want the other alliance members to be good enough to create attractive products on their part. But, second, it's also gamble that consumers that do pick alliance products will pick the Pentax variants of those products. That has the paradoxical implication that Pentax does not want the other alliance members to be so good as to outcompete Pentax on bodies and lenses. That is, Pentax must believe the alliance members are good but not too good!

Any new mount is basically a "back-to-square-one" experience for a camera company that takes huge investment to create new products fitting the new standard. Thus, joining an alliance is a high-cost, high-risk strategy.

Staying with the K-mount is a low-cost strategy and enables Pentax to build incrementally better products with incremental investment rather than starting from scratch. Whether K-mount is a risky strategy depends on the future of DSLRs. That future has less to do with mirrorless than many think. Even if MILCs gain marketshare, even if MILCs become very popular, that does not imply a company cannot be successful making DSLRs for people who want DSLRs. Many types of products can coexist in the market.
Forum: Flashes, Lighting, and Studio 6 Days Ago  
Best Flash for automotive photography
Posted By photoptimist
Replies: 23
Views: 592
You can solve or at least reduce flash reflections off chrome, glass, and shiny paint by polarizing the light from the flash and using a polarizing filter on the lens to block directly-reflected hotspots. See Get Amazing Flash Photos With a Simple Polarized Flash Modification.: 6 Steps for instructions and sample photos.

P.S.: you'll get best results with a high-quality polarizing filter and film materials. Cheaper polarizers will tend to produce blue or brown hotspots.

P.P.S. Old laptops, tablets, and smart phones tend to have very high quality polarizing films because that determines the quality of the black levels of the LCD display. A bit of scavenging and careful peeling of the film can yield a decent sized piece for putting over a flash.
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