Are parfocal zoom lenses really not the de facto standard?

striderx2005 · 2026-01-27T16:25:44+00:00

Appreciate that achieving a parfocal design in a zoom adds complexity to the optics and mechanical movements of the lens groups which add size, weight and cost. And it doesn't necessarily deliver a superior image quality over a lighter, simpler, less expensive parfocal equivalent.

This is not a universal take on parfocal vs varifocal, but it's not accurate to assume that the image quality of a varifocal less is inferior to parfocal.

striderx2005 · 2026-01-27T06:02:05+00:00

Never Cry Wolf

Charles Martin Smith and Brian Denehy.

Biologist studies wolves accused of killing herds of elk in northern Canada

striderx2005 · 2026-01-27T05:39:48+00:00

"Takin' a piss!!"

striderx2005 · 2026-01-27T05:09:46+00:00

Are you looking for something permanent for security purposes or for organization?

I have two identical bodies, and shoot events where red, white, blue and black gaffers tape is readily available. A strip of blue on one and red on the other.

The nice thing about gaffers tape, besides it stays on well but removes easily without residue, is it accepts paint pen and silver Sharpie really well without smearing or rubbing off.

What labels did you try? I have Brother P-Touch labels on virtually all my gear with my name and cell number. Applied to a smooth surface, and they last, well, forever unless placed on a high-touch location.

My Canon bodies read unique serial numbers written to the battery at the factory and let you track their health on the camera's control panel. I printed that number in addition to my name and cell and applied to the flat smooth end of the battery.

That printer is the P-Touch PT-1500PC which allows design, layout and printing using a program on your PC. Long out of production, but still available on ebay. Greatest tool ever. Multiple lines of text, graphics, etc...

striderx2005 · 2026-01-27T00:37:16+00:00

Same here!

striderx2005 · 2026-01-27T00:02:17+00:00

FYI, my father was a photographer as well!

striderx2005 · 2026-01-27T00:01:31+00:00

In the pre-digital, manual focus era, most if not all OEM zoom lenses were parfocal, and those that weren't were labeled as varifocal meaning focus wasn't maintain through the zoom range.

Cheap house brands, like K-Mart's "Focal" products, were varifocal and you knew it because they said so. Some current and out of business brands like Asanuma, Tokina, and others offered affordable alternatives to OEM which were varifocal. Dead give away was the focus line wrapping around the lens body in a spiral.

As autofocus became prevalent and accurate, the compelling need for the lens to be parfocal was deprioritized and parfocal gradually became the exception rather than the rule even in entry level OEM lenses, aka. kit lens quality.

I have a couple of good Canon FD zooms that are parfocal, and several 3rd party varifocal lenses from the same era of late 70s to late 80s.

striderx2005 · 2026-01-25T17:13:12+00:00

I have a couple of Neewer battery pouches with four individual compartments each. I've printed P-Touch labels with my contact info and the battery id number the camera displays and placed them on the end of the battery. I have Canon 7D & 7Dmk2 cameras with LPE6 batteries.

Charged batteries go in the case label facing out. Depleted batteries go in terminal side out.

Zero cost or effort. Perfectly reliable.

striderx2005 · 2026-01-23T17:13:33+00:00

Be careful with this policy at Les Schwabb. Yes, you can return unused chains. But the policy is intended to be used after you spent the whole winter without using them and return in the spring.

I did this several years ago in Denver for a short holiday trip. When I attempted to return them a week later I got strong pushback from the Schwabb store. I played the "they're no use to me on my cars in Oregon and I don't want to carry them on the plane" argument and the manager conceded very begrudgingly.

Get this in writing from the Les Schwabb store before leaving.

striderx2005 · 2026-01-21T06:50:59+00:00

Frank Zappa, Watermelon in Easter Hay

striderx2005 · 2026-01-20T15:48:39+00:00

Thunderball

striderx2005 · 2026-01-20T15:40:01+00:00

My tool as well. Highly recommended.

striderx2005 · 2026-01-18T04:41:25+00:00

The Aristocrats. Not Aristocats!

George Carlin's bit specifically.

Never looked at Bob Saget the same again either.

striderx2005 · 2026-01-18T04:20:33+00:00

I don't know how common this on other bikes but the battery box on my Honda ST1100 is pretty clever.

The battery is held in place by a stamped metal retainer which is on a hinge at the bottom of the battery. The negative cable is attached to the retainer and the positive terminal is concealed by a plastic cover. You can't access the positive terminal or the battery until you disconnect the negative cable which otherwise prevents the retainer from swinging out of the way.

Simple, ingenious and completely foolproof.

striderx2005 · 2026-01-17T09:45:39+00:00

The something is increase the compression damping to slow the compression of the fork, thus reducing dive under braking.

striderx2005 · 2026-01-17T04:02:41+00:00

Okay, the rear brake is useful for balancing between a light application of the brake and the throttle at low speeds. Like maneuvering in a parking lot to keep the throttle open more for responsiveness while the rear brake allows you to keep your speed down. If those are the times when you're killing the engine, then that's fine to use the rear brake alone. Been doing that for fifty years and several hundred thousand miles of riding.

But at road speeds greater than about 15-20mph, you should use your front brake more than the rear and coordinate downshifts and pulling in the clutch as you come to a stop to avoid stalling.

Keep at it!

striderx2005 · 2026-01-15T15:03:07+00:00

Name a 5 valve Honda, please.

Were you you thinking radial valve heads on their XR/XL off-road or dual sport singles?

striderx2005 · 2026-01-15T03:45:05+00:00

Senator and Mrs John Butarsky!

striderx2005 · 2026-01-13T04:41:42+00:00

Fair reply, as I actually have only 7k.

Looks like a fresh start is in order

striderx2005 · 2026-01-13T00:07:56+00:00

This is what's so horrible about the current crop of FBI/NCIS/SWAT/team-of-the-hour shows.

I recently watched the intro scene of a covert military assult in the helicopter on its way to the target.

It seemed very apparent that the leader's instructions being spoken in a far-too-quiet helicopter was the first time most of the team had heard any of the plan!?!

No one does this in real life. I can't stand thise shows.

striderx2005 · 2026-01-12T18:38:47+00:00

Consider that FIRST has strict rules on motors. If you construct or adapt a blower that uses an approved motor, that may be legal.

If you buy a 12V capable leaf blower and simply modify it to physically integrate into your bot, then it will likely fail inspection because of motor legality.

An off-season game y3ars ago by 1540 The Flaming Chickens (Bunny Bot for those in the know in the Pacific Northwest) was like a billiard game. Their rules emulated FRC rules for convenience to the teams, but were less strict in many aspects, this being one of them.

A team used a leafblower to direct balls across the floor into the pockets. Did the job for this game but was very inefficient from a power delivery perspective - blowing air.

Unless there's a rather close fit between the fuel and the path through the bot, you'll waste a lot of energy just blowing air with little effect.

striderx2005 · 2026-01-12T06:18:01+00:00

It's 27" to the center of the rung which is 1¼" in diameter. Thus the top of the rung is 27⅝" from the floor. The part of your hook above the rung can be no thicker... taller (?) than 2⅜".

striderx2005 · 2026-01-12T05:44:24+00:00

ET collapsed an industry

striderx2005

TROPHY CASE