Mike Davis

Lives in United States Dallas, United States
Has a website at http://www.accessz.com
Joined on Jun 12, 2002

Comments

Total: 132, showing: 1 – 20
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On article A fully loaded iMac Pro will cost you $13,200 (99 comments in total)

iMacs are great for people who live in tiny houses or in boats or RVs, where there's no space on top of a desk or on the floor to sit a big tower chassis that has lots of expansion bays and slots for countless hardware features, with numerous power supply, motherboard, CPU, GPU, storage, WiFi, memory and cooling options and the ability to upgrade those hardware components almost indefinitely or...

... to upgrade your monitor without having to toss the whole machine.

Link | Posted on Dec 14, 2017 at 22:15 UTC as 9th comment

Great article. With DoFMaster having been recommended, here's a deal currently available for the Bosch GLM 35 Laser Measurer:

https://www.dpreview.com/forums/post/60432962

Link | Posted on Nov 27, 2017 at 12:14 UTC as 1st comment
On photo The Worker in the environmental portrait challenge (7 comments in total)

I love this image, but... the application of HDR is little bit excessive for my tastes, which puts me among a minority, I admit. Still, it's a wonderful shot.

Link | Posted on Nov 27, 2017 at 11:58 UTC as 3rd comment
In reply to:

Mike Davis: "In fact, their 2018 sensor lineup includes two new MF sensors: a 100MP BSI 44x33 sensor and a 150MP BSI 55x41mm sensor."

100 MP on a 44x33mm sensor = a pixel density of 185.5 pixels/mm, requiring we stop down no further than f/11.3 to secure 5 lp/mm worth of actual subject detail in an uncropped, unreseampled 360 ppi print.

150 MP on a 55x41mm sensor = a pixel density of 257.9, requiring we stop down no further than f/8.1 to secure 5 lp/mm worth of actual subject detail in an uncropped, unresampled 360 ppi print.

In other words, thanks to diffraction, the larger yet denser 150 MP sensor cannot deliver 5 lp/mm worth of actual subject detail in unresampled 360 ppi prints without opening up one stop further than the smaller yet less dense 100 MP sensor.

I'll take the 100 MP sensor and be content with smaller prints at any given desired print resolution goal, to enjoy one additional stop worth of creative freedom, without concern for diffraction inhibiting my print resolution goal.

The f-Number at which diffraction BEGINS to inhibit a desired print resolution, for an anticipated enlargement factor and viewing distance, can be calculated as follows:

f-Number = (viewing distance in cm / desired final-image resolution in lp/mm for a 25 cm viewing distance / enlargement factor / 25) / 0.00135383

8 lp/mm at a viewing distance of 25 cm is considered to be the limit of human visual acuity. A figure of 5 lp/mm was used for my earlier comments, above.

Link | Posted on Nov 17, 2017 at 14:23 UTC
In reply to:

Mike Davis: "In fact, their 2018 sensor lineup includes two new MF sensors: a 100MP BSI 44x33 sensor and a 150MP BSI 55x41mm sensor."

100 MP on a 44x33mm sensor = a pixel density of 185.5 pixels/mm, requiring we stop down no further than f/11.3 to secure 5 lp/mm worth of actual subject detail in an uncropped, unreseampled 360 ppi print.

150 MP on a 55x41mm sensor = a pixel density of 257.9, requiring we stop down no further than f/8.1 to secure 5 lp/mm worth of actual subject detail in an uncropped, unresampled 360 ppi print.

In other words, thanks to diffraction, the larger yet denser 150 MP sensor cannot deliver 5 lp/mm worth of actual subject detail in unresampled 360 ppi prints without opening up one stop further than the smaller yet less dense 100 MP sensor.

I'll take the 100 MP sensor and be content with smaller prints at any given desired print resolution goal, to enjoy one additional stop worth of creative freedom, without concern for diffraction inhibiting my print resolution goal.

If we all made the same size prints, whether shooting with a 10 MP sensor or a 150 MP sensor....

If enlargement factor was the same for a given print size, no matter the dimensions of the sensor...

If we all had the same print resolution goals to support the same anticipated viewing distance...

... people who reject the impact of these factors would actually make sense. f-Number (and the wavelength of light) would be the only factor(s) that affect the diffraction we perceive. And, for anyone who still doesn't get it, nobody can perceive what's happening at the sensor plane. It's all about what's perceived in the final print, after enlargement, at the viewing distance which is itself variable.

Link | Posted on Nov 17, 2017 at 14:23 UTC
In reply to:

Mike Davis: "In fact, their 2018 sensor lineup includes two new MF sensors: a 100MP BSI 44x33 sensor and a 150MP BSI 55x41mm sensor."

100 MP on a 44x33mm sensor = a pixel density of 185.5 pixels/mm, requiring we stop down no further than f/11.3 to secure 5 lp/mm worth of actual subject detail in an uncropped, unreseampled 360 ppi print.

150 MP on a 55x41mm sensor = a pixel density of 257.9, requiring we stop down no further than f/8.1 to secure 5 lp/mm worth of actual subject detail in an uncropped, unresampled 360 ppi print.

In other words, thanks to diffraction, the larger yet denser 150 MP sensor cannot deliver 5 lp/mm worth of actual subject detail in unresampled 360 ppi prints without opening up one stop further than the smaller yet less dense 100 MP sensor.

I'll take the 100 MP sensor and be content with smaller prints at any given desired print resolution goal, to enjoy one additional stop worth of creative freedom, without concern for diffraction inhibiting my print resolution goal.

Yes, Tommi K1. Thank you. Viewing distance, enlargement factor and f-Number all affect the impact diffraction will have on inhibiting a desired print resolution.

Make a larger print, all else remaining the same, and diffraction's Airy disks will become larger, reducing the print resolution.

Shrink your sensor, all else remaining the same, and diffraction's Airy disks will become larger, reducing the print resolution.

Reduce your viewing distance, all else remaining the same, and diffraction's Airy disks will appear to be larger, reducing the apparent print resolution.

Add more pixels to a sensor and you'll be tempted to make a larger print, thanks to having 100 MP vs. 50 MP, for example, but if you do, your enlargement factor will increase if the sensor dimensions were not also increased along with the pixel count. You will have to open your aperture to prevent diffraction's Airy disks from becoming "visibly" larger in the larger print to be viewed at the same distance.

Link | Posted on Nov 17, 2017 at 14:15 UTC
In reply to:

Mike Davis: "In fact, their 2018 sensor lineup includes two new MF sensors: a 100MP BSI 44x33 sensor and a 150MP BSI 55x41mm sensor."

100 MP on a 44x33mm sensor = a pixel density of 185.5 pixels/mm, requiring we stop down no further than f/11.3 to secure 5 lp/mm worth of actual subject detail in an uncropped, unreseampled 360 ppi print.

150 MP on a 55x41mm sensor = a pixel density of 257.9, requiring we stop down no further than f/8.1 to secure 5 lp/mm worth of actual subject detail in an uncropped, unresampled 360 ppi print.

In other words, thanks to diffraction, the larger yet denser 150 MP sensor cannot deliver 5 lp/mm worth of actual subject detail in unresampled 360 ppi prints without opening up one stop further than the smaller yet less dense 100 MP sensor.

I'll take the 100 MP sensor and be content with smaller prints at any given desired print resolution goal, to enjoy one additional stop worth of creative freedom, without concern for diffraction inhibiting my print resolution goal.

Thanks guys. My mistake. Uggh!

I've just redone the math and have come up with the same numbers as @thx1138.

They indeed have essentially identical pixel density. If your goal is to deliver 5 lp/mm in an uncropped, unresampled 360 ppi print, this means both cameras will have to avoid stopping down below f/8, thanks to diffraction.

When making prints as large as these pixel counts encourage, densities exceeding 200 pixels/mm begin to encroach on the selection of stops one can use without diffraction inhibiting a print resolution of 5 lp/mm. 200 pixels/mm is a "line in the sand" seldom crossed by MF sensor designs. 260 is a bit confining.

If you are willing to make smaller prints or you have a print resolution requirement that's less than 5 lp/mm, you can stop down further than f/8.0 with these two sensors, but it's ironic that with so many MP, several of the largest f-Numbers available on MF lenses must be avoided to produce the biggest prints supported by the pixel count.

Link | Posted on Nov 17, 2017 at 01:06 UTC
In reply to:

GregFranklin: "Did it do anything that I couldn't with a Raw file and about 30 seconds of post processing? Heck no. But the point is that this is the new normal for a lot of people who take pictures and have no interest in pulling shadows in Photoshop."

Perfectly said.

@fatdeeman ... or worse, they come up with far less natural looking results, intentionally.

I really have to hand it to this automated HDR for practicing a "less is more" aesthetic.

Link | Posted on Nov 17, 2017 at 00:32 UTC
On article Hasselblad launches 'Rent a Hasselblad' service (54 comments in total)
In reply to:

Akpinxit: None in sane mind would hold such camera without strap like a guy on headline image .

Maybe they're hoping to increase revenue by enforcing a "You broke it, you bought it" policy.

Link | Posted on Nov 16, 2017 at 23:21 UTC
On article Hasselblad launches 'Rent a Hasselblad' service (54 comments in total)
In reply to:

CaPi: What a sad website.
They wont tell you where you can rent unless you get a user with email etc first.
e.g.
Canada: Calgary, Toronto, Montreal
Germany: Essen Hamburg Munich Stuttgart (Calumet)
US: Denver, Aurora, Livonia, SF, Austin, NYC, Chicago, Salt Lake City, Seattle

They should have setup rentals via FedEx.

Link | Posted on Nov 16, 2017 at 23:19 UTC

"In fact, their 2018 sensor lineup includes two new MF sensors: a 100MP BSI 44x33 sensor and a 150MP BSI 55x41mm sensor."

100 MP on a 44x33mm sensor = a pixel density of 185.5 pixels/mm, requiring we stop down no further than f/11.3 to secure 5 lp/mm worth of actual subject detail in an uncropped, unreseampled 360 ppi print.

150 MP on a 55x41mm sensor = a pixel density of 257.9, requiring we stop down no further than f/8.1 to secure 5 lp/mm worth of actual subject detail in an uncropped, unresampled 360 ppi print.

In other words, thanks to diffraction, the larger yet denser 150 MP sensor cannot deliver 5 lp/mm worth of actual subject detail in unresampled 360 ppi prints without opening up one stop further than the smaller yet less dense 100 MP sensor.

I'll take the 100 MP sensor and be content with smaller prints at any given desired print resolution goal, to enjoy one additional stop worth of creative freedom, without concern for diffraction inhibiting my print resolution goal.

Link | Posted on Nov 16, 2017 at 23:07 UTC as 38th comment | 12 replies

No batteries needed to operate this camera? I'm going to buy a hundred of these and sell them after the big EMP hits us. I'll stack them next to the TP. Oh wait... the TP will probably sell better. Never mind.

Link | Posted on Nov 15, 2017 at 23:36 UTC as 126th comment
In reply to:

Joel Pimenta: The right product for James Cameron!

Actually, from what I've heard, he always prefers to reinvent the wheel rather than seeking the expertise of people who've already been down the path he's on.

Link | Posted on Nov 15, 2017 at 23:27 UTC
In reply to:

chshooter: Unless there is some sort of automatic stitching, a result that is free of any motion artifacts and fast enough burst rate to shoot 90% of all scenes that way this is an utterly useless feature and just a marketing gimmick. I only see a use for still life photography in the studio since there is always some cloud or foliage movement in real life

Imagineering a solution is much easier than actually making it happen, of course, but with sufficient processing speed, enhanced firmware should be able to identify the areas in which motion-induced artifact has occurred, to which a correctly vectored motion blur could be automatically applied, in-camera, to replicate what one would see had they made a single exposure of a duration equal to the total gap between multiple shifted exposures. And while I'm day-dreaming from my armchair, why not make it a user-selectable option?

A much simpler, non-solution, but very helpful aid, would be that of only identifying the areas of artifact by blinking them on and off or color-filling them in a post-exposure display mode, as is typically done to identify areas of overexposure. This would at least warn the user that he might want to wait for less of a breeze with outdoor scenes for example.

Link | Posted on Nov 13, 2017 at 15:07 UTC
In reply to:

Bmark: I have done underwater photography for many years and I always say its not if you will flood your camera its when. I've flooded both a D300 and a D800 in ocean water and both were immediately dead. Even if the camera is waterproof, which it is not, is the lens waterproof? Even though I immediately opened and rinsed the cameras in clean water they would no longer operate after drying out and the controls, buttons, etc. began to seize up after only a couple of days. Both cameras were sent to Nikon for evaluation (I had flood insurance) and determined to be unrepairable.

Roger that - it's just a matter of when. I gave up on protecting expensive cameras and decided the safest bet is to buy an Ikelite case (waterproof to several meters) for a camera that costs about half as much as the case itself. If you NEGLECT to carefully clean and lubricate the o-rings, you can end up with a flooded camera, but... it will be relatively inexpensive to replace. The case will be just fine after you rinse it out, clean it and dry it - ready for the next victim. Peace of mind.

Link | Posted on Nov 10, 2017 at 00:53 UTC

1:05 through 1:08 was the most entertaining segment of the video. I want one! (Not)

Link | Posted on Nov 10, 2017 at 00:39 UTC as 17th comment
On article Sigma's new 16mm F1.4 will cost $450, ships this month (359 comments in total)
In reply to:

digitallollygag: This has to be the bargain of the year

Before I heard the price, I was wishing Sigma had made a slightly slower, smaller and lighter 16mm prime, with the fringe benefit that it would be less expensive, too.

Now, I'm thinking... at THIS price, I will just put up with the fact that it's big, heavy, and FAST! :-)

If it performs in keeping with Sigma's reputation, this thing will sell like the a6000 has sold.

Link | Posted on Nov 10, 2017 at 00:13 UTC
In reply to:

vscd: Stop this lomo-nonsense. Give us some serious film-emulsions, and even better... give them as 220 rolls. There are thousands of backs out there and no existing 220 roll. This would be a unique selling point instead of this stupid hipster-thingy.

@cdembrey Thanks! I experimented with the ExpoDisc back in the day. For the past 16 years, I've been using a DIY, 6x6-inch diffuser, made with two sheets of translucent white acrylic in a 1/4-inch balsa wood frame, sandwiching a 1-stop, acetate ND filter - for applying pre-exposure when shooting 120 Velvia or Provia, per this Excel spreadsheet:

http://www.accessz.com/tools/Flash42.xls

Also see the Articles tabs at the bottom of the workbook - especially the "How to use it in the field" portion, in the second half of "Article 2."

Link | Posted on Oct 31, 2017 at 17:33 UTC
In reply to:

vscd: Stop this lomo-nonsense. Give us some serious film-emulsions, and even better... give them as 220 rolls. There are thousands of backs out there and no existing 220 roll. This would be a unique selling point instead of this stupid hipster-thingy.

Great suggestion and the best comment here, in my opinion.

This wouldn't be of interest to me, either, but even a film offered with various amounts of uniform and neutral pre-exposure would be more useful (for raising shadows a wee bit when shooting high contrast scenes.)

Link | Posted on Oct 30, 2017 at 17:15 UTC
In reply to:

BacktotheFuji: "In person, the new lens is a small, but beautifully well-made prime"

Um, granted I'm not there in person, but it doesn't look particularly small to me :D

A 16mm f/2 prime would be much more appealing to me (in size, weight and price). I should think most landscape and architecture shooters would want a slower lens as well - just because they typically need more DoF than would be available at f/1.4. I'll be sticking with my Sony 10-18mm f/4, which does a much better job at 16mm than does the 16-55mm kit lens.

Link | Posted on Oct 27, 2017 at 22:33 UTC
Total: 132, showing: 1 – 20
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