Date: 11/29/18 3:38 pm
From: Nagi Aboulenein <nagi.aboulenein...>
Subject: [obol] Re: Dharma Center Bluebirds and a request from OBOL members
Hi Lars,

> > I'm always mystified why someone with that big a lens has to get so much closer than the rest of us.

That question, I can help with :-)

The large DSLR super-telephoto lenses, as they’re referred to, don’t necessarily have a huge focal length or magnification factor, which, by the way is not the same as the “zoom” factor.

The zoom factor only applies to variable focal length (zoom) lenses (as opposed to fixed focal length lenses), and refers to the ratio between the shortest and longest focal lengths of a zoom lens, and basically has nothing to do with how much closer or how magnified an image will appear to be. For example, both a 15-60mm lens and a 100–400mm lens will both have a zoom factor of 4, but obviously the 100-400mm lens will bring things a lot closer, or have a larger magnification factor.

The magnification factor is all about how much the object will appear magnified relative to approximately what’s seen by the human eye at the same distance. The human eye is approximately equivalent to a 50mm lens in that respect, so a 500mm lens will “only” give you a 10x magnification, about the same as 10x binoculars. That’s pretty meagre, when compared to what some of the more recent point-and-shoot cameras are capable of. For example, Nikon’s most recent P&S camera (P1000, I think) has a focal length of up to 3000mm. When fully extended, that’s a 60x magnification vs. the human eye or a 50mm lens, or 6x larger than a DSLR 500mm lens.

However, where these P&S cameras fall short is in how much light enters the lens and consequently hits the sensor, due to the smaller size of the lens as well as the smaller size of the sensor. The amount of sharpness and detail you get with one of these DSLR monster lenses is amazing compared with a superlong P&S's sharpness and detail. Additionally, the severity of atmospheric effects on image quality (heat shimmer, etc) is directly proportional to the distance from the object - so that the longer the camera’s lens, the more exposed you are to image degradation due to such effects.

Cheers,

Nagi (who will happily expound on cameras and lenses all day long, potentially at the risk of boring his audience to death)
On Nov 29, 2018, 3:07 PM -0800, Lars Norgren <larspernorgren...>, wrote:
> I'm always mystified why someone with that big a lens has to get so much closer than the rest of us. The prairie is old driving range,  not property of DRZC. l hope Metro can acquire or lease it. The policy on DRZC property is "all trails and natural areas" are open to public in daylight. The birds have been ranging far and wide since at least Monday w/o it seeming to be a response to human presence. Tuesday they went from the prairie to the sports field west of 82nd and back about three times in under two hours. Hopefully they're habituated. Lpn
>
> > On Thu, Nov 29, 2018, 2:17 PM Nagi Aboulenein <nagi.aboulenein...> wrote:
> > > Well said, David. Where there is a choice to be made between getting a good photo and not disturbing/harassing the bird (or other wildlife creature), the latter should always win out.
> > >
> > > A good reference for ethical bird photography is at https://www.audubon.org/get-outside/audubons-guide-ethical-bird-photography. It can also be generalized readily to be applicable to general wildlife photography, not just birds.
> > >
> > > Nagi
> > > On Nov 29, 2018, 1:43 PM -0800, David Bailey <davidcbaileyoregon...>, wrote:
> > > > The photographer as described was extremely selfish to approach a stakeout so closely. If the birds are harassed they could find s new sight and many hopeful birders may lose out on a memorable twitch. Unfortunately, this happens often with overzealous photographers and stakeout bird, especially the charismatic species like Snowy Owls and of course bluebirds. Sometimes these folks are birders/twitches and sometimes they are more hobbies photographers. Either way, shame on them.
> > > >
> > > > David C. Bailey
> > > > Seaside Oregon
> > > >
> > > >
> > > >
> > > > > On Thu, Nov 29, 2018, 13:22 Jim Danzenbaker <jdanzenbaker...> wrote:
> > > > > > OBOLers,
> > > > > >
> > > > > > I made the pilgrimage to see the Eastern Bluebirds this morning.  After a half hour wait, they magically appeared (~!!:30) in their usual hover hunting behavior close to the "yellow tree" to the west of the Dharma Center parking lot.  Thanks to those who have posted directions and tips for seeing these birds.
> > > > > >
> > > > > > While I was there, several birders mentioned to me that the bluebirds had been in the field before I arrived but were no longer there due to a photographer who had walked out into the field with his long camo covered lens and was sitting on the ground next to the "pond" waiting for the birds to return.  If he was trying to stay camouflaged, it didn't work since he wore a bright yellow jacket.  I had a problem with this for several reasons:
> > > > > >
> > > > > > 1.) Walking out into the field where there were no trails.  I thought this was Dharma Center property.
> > > > > > 2.) Positioning oneself right next to where the bluebirds were known to favor.
> > > > > >
> > > > > > I took a recognizable photo of the photographer.  When the bluebirds did return, the photographer increased his height so he could get more photographs.  This reduced the amount of time that the bluebirds stayed at the location.  Within about 5 minutes, the bluebirds left again.
> > > > > >
> > > > > > Question for the OBOL community:
> > > > > >
> > > > > > 1.) Should I publicly shame this photographer for his behavior (encroaching on the bluebirds and walking out in the field) and post a photo of him to OBOL.*
> > > > > > 2.) Should I forget it and move on.
> > > > > >
> > > > > > * given that OBOL or OBA has a regular photo contest, I don't want this photographer to get credit for a great photo given what he did to get it.
> > > > > >
> > > > > > Please e-mail me privately with your feedback.
> > > > > >
> > > > > > I know that the bluebirds have been returning to this location and may have been here for two months and may well stay here for the entire winter.  I don't think this means that its ok for people to walk out into the field to get a photograph which may adversely affect the movements and feeding habits of these birds.
> > > > > >
> > > > > > Thanks for your patience in reading this and I appreciate your feedback.
> > > > > >
> > > > > > Keep your eyes and ears skyward.
> > > > > >
> > > > > > Jim
> > > > > > --
> > > > > > Jim Danzenbaker
> > > > > > Battle Ground, WA
> > > > > > 360-702-9395
> > > > > > <jdanzenbaker...>

 
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