Peter Cockerell

Joined on Mar 7, 2012

Comments

Total: 43, showing: 1 – 20
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In reply to:

John Koerner: Another yawner for the macro world.

* 270° of focus throw = every other iteration of every other lens in this class.
* Rubber focus ring? Is that supposed to be a bonus?
* 1:1 = every other iteration of every other lens in this class.
* Zero distortion = whoop-de-do, same story.
* 12.3" of Minimum Focusing Distance = less than the competition (some offer up to 18" MFD)

If you're going to jump into the fray, at least do something different, something distinguishably-excellent, or don't even bother.

@MyReality "Raised my camera to my eye, never stopped to wonder why..."

Link | Posted on Sep 25, 2018 at 07:46 UTC
In reply to:

breschdlingsgsaelz: Wow, this camera is designed to be sold by spec sheet. What do you want to do with a 3.000mm f/45 equivalent lens? For 500mm+ focal length even f/11 on full frame is pretty much useless, what do you want to photograph with f/45?

Well, yes, maybe the moon. But if you want to use an ISO setting that still looks o.k. you will probably need a motorized tripod head which follows the moons movement to get a long enough exposure...

You seem to be implying that the "equivalent" f-number should be used to calculate the exposure time, which of course is not the case, and at f/11, ISO 100, a 1/30s should be perfectly fine for the moon in its first or last quarter.

At 3000mm, the 500 rule gives a 1/6s maximum shutter to avoid blurring owing to the Earth's rotation, so no motor drive required!

Link | Posted on Jul 10, 2018 at 06:54 UTC
In reply to:

Digitalis32: As a large format photographer this sensor fails to impress. You can get polaroids bigger than that.

But the sensor doesn't claim to be a large format photographer, so your point is moot.

Link | Posted on Jun 19, 2018 at 04:01 UTC
In reply to:

vscd: Sounds to me like: What? Judean People's Front? We're the People's Front of Judea!

Splitters!

Link | Posted on May 24, 2018 at 20:15 UTC
In reply to:

Peter Cockerell: "The compression you get using a long lens isn't a result of the lens, so much as the distance between your subject, your background, and the camera."

God but these pedantic distinctions are tiresome. It may not be a result of the lens, but its observability is. If I take a shot of layered, misty mountain peaks in the far distance with a 400mm + 1.4x teleconverter, the "compression" (for want of a better term) is very obvious. If I take the same shot with a 16mm wide angle, the area covered by the original photo will occupy about 0.1% of the wide-angle shot, and will be totally lost in the rest of the image.

No, the 640mm didn't create the compression, it just enables you to actually see it. I think most people understand this, implicitly, even if they don't necessarily articulate it. People who make videos like this are much more annoying in my opinion than people who say "lens compression". It's not even new or original. The same tired "explanations" come round time and time again.

@starbase218 Yes, a 0.9mm x 0.6mm sensor for the 16mm lens! Seen many of those around? It would be diffraction limited to hell, so there's no way you'd get anything like a comparable (quality) image to the 640mm* on a full frame. And that was MY point. Practically speaking, it IS that lens that allows you to get the image. As you scale things down, you lose quality. Yes, an MFT with a 320mm will get you something close, but not a an Exmor phone sensor with a 70mm lens (not a common sight on mobile phones!) Size matters! And in all those cases, it's still the 640mm *equivalent* lens that's giving you the image. I for one tend to think in 35mm focal lengths, even though I've used MFT, APS-C and full frame.

* Actually 560mm, I can't multiply! But I stuck with 640mm for the sake of consistency.

Link | Posted on May 24, 2018 at 09:48 UTC
In reply to:

Silvex: Photography is littered with imprecise, ambiguous or otherwise vestigial terminology. How about we start with the video creator's name sake?

f-stop: It's really not a "stop" at all. When someone says "Increase your f-stop" half of the crowd thinks something different than the other half.

Hot Shoe - Definitely not a shoe and well it isn't normally hot is it.

Shutter speed - It actually moves at the same speed every single time; no matter what the time value is.

ISO - About half of all photographers think this is an acronym pronounced: I-S-O.

Bulb - Well nobody uses an actual rubber bulb anymore do they.

Exposure triangle - Nothing to do with geometry; 3 items, a triangle has 3 sides. If we add a ND filter would it be an exposure square? Becomes a pentagon with a flash?

Bokeh - My personal favorite. As if people weren't already confused, let's throw in a word from a foreign language. Everyone is still arguing about how to pronounce it.

No space for glass or fast glass ;-(

Silvex, the reason your ISO point was confusing is that there's no such thing as an acronym that's pronounced I-S-O. By definition, an acronym is an abbreviation that's pronounced as a word. What you meant is that people think that ISO is an *abbreviation* pronounced I-S-O.

Link | Posted on May 24, 2018 at 05:52 UTC

"The compression you get using a long lens isn't a result of the lens, so much as the distance between your subject, your background, and the camera."

God but these pedantic distinctions are tiresome. It may not be a result of the lens, but its observability is. If I take a shot of layered, misty mountain peaks in the far distance with a 400mm + 1.4x teleconverter, the "compression" (for want of a better term) is very obvious. If I take the same shot with a 16mm wide angle, the area covered by the original photo will occupy about 0.1% of the wide-angle shot, and will be totally lost in the rest of the image.

No, the 640mm didn't create the compression, it just enables you to actually see it. I think most people understand this, implicitly, even if they don't necessarily articulate it. People who make videos like this are much more annoying in my opinion than people who say "lens compression". It's not even new or original. The same tired "explanations" come round time and time again.

Link | Posted on May 24, 2018 at 05:43 UTC as 58th comment | 8 replies
In reply to:

Peter Cockerell: Load the images into an image stack in Photoshop, with "auto align" checked. Use the Difference mode to see where the layers are different. The sky becomes incredible dark, implying the contents are practically the same.

On the other hand, if you use "free transform" on the top layer to align the bottom of the photos more perfectly, the clouds do take on more of a classic "cloud drift" look.

I think it's possible to go either way, but for me, since buildings tend to move less than clouds, I'm veering towards two photos taken from very close locations at slightly different times. That doesn't explain the bird, but then I couldn't find it anyway!

Sorry, I didn't notice (and see other people pointing out) that the foliage on the trees is entirely different. Obviously the sky is cloned from Elia's photo!

Link | Posted on Jan 12, 2018 at 21:03 UTC

Load the images into an image stack in Photoshop, with "auto align" checked. Use the Difference mode to see where the layers are different. The sky becomes incredible dark, implying the contents are practically the same.

On the other hand, if you use "free transform" on the top layer to align the bottom of the photos more perfectly, the clouds do take on more of a classic "cloud drift" look.

I think it's possible to go either way, but for me, since buildings tend to move less than clouds, I'm veering towards two photos taken from very close locations at slightly different times. That doesn't explain the bird, but then I couldn't find it anyway!

Link | Posted on Jan 12, 2018 at 19:16 UTC as 61st comment | 7 replies
On article Olympus 45mm F1.2 Pro sample gallery updated (344 comments in total)
In reply to:

Franz Weber: Feathered bokeh is only needed when birding. For shooting horses it just makes no sense.

Bokeh is never the mane consideration when shooting horses.

Link | Posted on Dec 12, 2017 at 20:20 UTC
In reply to:

Ruy Penalva: Now let's await the answering of Pyongyang!

You're concerned that Kim Jong Un is going to nuke the HuaWei factory? Surely that would alienate DPRK's one remaining (kind of) ally...

Link | Posted on Oct 17, 2017 at 04:23 UTC
In reply to:

Suntan: After a couple of years of people rioting in the streets calling for dead cops, as well as numerous occurrences of cops being gunned down at random, out of no-where, across the country; now cops are quite jumpy.

Imagine that.

There's a difference between being "quite jumpy" and opening fire with zero warning (and presumably zero confirmation that there actually was a threat, seeing as there wasn't). Do these cops receive any screening/training at all? And, BTW, the number of cops killed by firearms in 2016 was 64. 64 too many, perhaps, but hardly an epidemic.

Link | Posted on Sep 5, 2017 at 19:00 UTC
In reply to:

Bambi24: "police are trigger happy"

You'd be too if every lunatic walked around with a gun, able to take your life in a split second.

Don't point cameras at cops in the middle of the night -> you won't get shot.

Why is there no "Unlike" button here?

Link | Posted on Sep 5, 2017 at 18:55 UTC
In reply to:

Okapi001: It seems the Deputy is in fact a Wesen. That would explain everything;-)

If only he'd woged before he opened fire, the photographer would have stood a chance.

Link | Posted on Sep 5, 2017 at 18:53 UTC
In reply to:

Cary Knoop: From the article: "4:2:2 10-bit codec is 64x as much data as before"

No it isn't!

10 bit is 4 times as much data as 8 bit and 4:2:2 is 1 1/3 times as much data as 4:2:0, so it is 5 1/3 times as much not 64 times as much.

J A C S you are definitely confusing the phrase "amount of data" with "number of representable values". A ten-bit value is able to represent four times the number of values of an eight-bit one, but no-one (other than you) would claim it amounts to four times as much "data". It takes 25% more storage, requires 25% more time to transfer (serially, all things being equal) etc. Maybe the problem is more one of language than math, but you're definitely using very non-standard terminology.

Link | Posted on May 9, 2017 at 06:49 UTC
In reply to:

Zdman: You forgot the main advantage which is lens design. To achieve the same depth of field and light gathering you can design a lens one stop higher than you would for full frame. So instead of making design trade offs with a F2 design you can go to F2.8 with less spherical aberration and chromatic abberations etc. Go to large format and you can design crazy good F5.6 lenses and still get the depth of field of a full frame at f1.4. Why do you think large format hasn't got lenses much faster than F5.6? Because they don't need it (the DOF would be too small) and the results at F5,6 are spectacular. Its not just about the silicon its the lenses. Extrapolate the MF F2.8 (which would probably only need 6 elements) and light gathering to M43 and you'd need an F1 lens which is just not feasible to design.

" Go to large format and you can design crazy good F5.6 lenses and still get the depth of field of a full frame at f1.4."

Only if the "large" format camera had a crop factor of 0.25x and a sensor area 16 times that of a full-time camera. Which model is that, and how much does it cost?

Link | Posted on Mar 23, 2017 at 17:02 UTC
In reply to:

Greg Gebhardt: Kinda shows how China is getting way ahead of us. All the wonders in the world are no longer here.

Only the most parochial-minded of Westerners would ever have believed all the wonders of the world were "here".

Link | Posted on Feb 25, 2017 at 17:34 UTC
On article Sigma Announces 100-400mm F5-6.3 DG OS HSM lens (154 comments in total)
In reply to:

janist74: Sigma is very clever.

They address the "size disadvantage" of FF/APS-C cameras (instead of Canon/Nikon). This lens is barely bigger than the Pana 100-400 MFT lens ( a tad slower and heavier though). If the IQ is good enough for an APS-C 24mP camera, then it will sell very good.

ps.: my only reservation: if the Pana 100-400mm has quite strong vignetting with a filter thread of 72mm then what this lens can do with 67mm...

Yep! ! was using 1.5-1.6 as the APS-C:MFT factor instead of the correct (2 over that number), i.e. 1.25-1.33, so my MPixel counts for APS-C should have been 20-21.3M pixel. So as you say, current APS-C sensors do have a slight pixel density advantage over older MFT ones, but not, I think, over a 20.3M pixel GH-5

Link | Posted on Feb 22, 2017 at 02:26 UTC
On article Sigma Announces 100-400mm F5-6.3 DG OS HSM lens (154 comments in total)
In reply to:

janist74: Sigma is very clever.

They address the "size disadvantage" of FF/APS-C cameras (instead of Canon/Nikon). This lens is barely bigger than the Pana 100-400 MFT lens ( a tad slower and heavier though). If the IQ is good enough for an APS-C 24mP camera, then it will sell very good.

ps.: my only reservation: if the Pana 100-400mm has quite strong vignetting with a filter thread of 72mm then what this lens can do with 67mm...

+NetMage No, because to confer the kind of digital zoom advantage that you imply, the larger sensor camera would need a greater pixel density, not just greater pixel count. Even for a trailing-edge 16M pixel MFT sensor, an APS-C sensor would need to exceed 36-41M pixels and a full-frame would need to exceed 64M pixels. I don't know of any available cameras that meet those requirements (and of course the numbers are even greater for a newer 20M pixel MFT sensor).

Link | Posted on Feb 21, 2017 at 15:47 UTC
In reply to:

Jefftan: These adapter won't work with EF-S lens as far as I know
They are for full frame EF lens

any EF-S to E adapter for Sony APS-C camera

Thanks

Though of course you wouldn't want to use a speed booster adapter with an ef-s lens on an aps-c body, or you'll get severe vignetting.

Link | Posted on Jan 25, 2017 at 18:36 UTC
Total: 43, showing: 1 – 20
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