propeller artifacts... please explain the horizontal lines.. (Page 2): :sm24: :sm24: :sm24: :sm24: :sm24:...

jeep_daddy Loc: Prescott AZ

rehess wrote:

The important search phrase is "rolling shutter"

JPL

billgdyoung wrote:

this image was taken with iPhone... don't know the f-stop, shutter speed, ISO... just shot thru the wind shield. Why the horizontal lines? Something to do with the way the phone's shutter or sensor scans?

This is rolling shutter effect. It means that your Iphone takes so long time to read the picture from the sensor that things in the picture that are moving fast will show some deformations. In this case the plane propeller.

billgdyoung Loc: Big Bear City, CA

JPL wrote:

This is rolling shutter effect. It means that your Iphone takes so long time to read the picture from the sensor that things in the picture that are moving fast will show some deformations. In this case the plane propeller.

thanks

Nikonman44

absolutely right. the phones shutter sheet is your culprit along with the glass wnshields effect on the phones lens.

dyximan

bkyser wrote:

Easy peasy....If you don't want to answer a question, then move on to the next thread.
Places like UHH are made specifically for people to ask and answer questions. Maybe it's you that should be somewhere else.
Were you never a beginner? Why do you come here, other than to belittle people who come for knowledge?

Thank you bkyser

wdross Loc: Castle Rock, Colorado

billgdyoung wrote:

this image was taken with iPhone... don't know the f-stop, shutter speed, ISO... just shot thru the wind shield. Why the horizontal lines? Something to do with the way the phone's shutter or sensor scans?

I believe you are seeing the propeller but not the way you expected to see it. It is being made to look like that by the way your cellphone is pulling the data off the sensor and the speed of the propeller. One of the many possible effects one can create with an electronic shutter.

sloscheider Loc: Minnesota

billgdyoung wrote:

I agree...but why the horizontal lines... the prop is going in circles....btw, the engine was running about 2500rpm

Lets say the 1st half of the prop comes along counter clockwise (from the cameras point of view), in the time it takes for the prop to travel from right to left the camera scans 50 lines lines (top to bottom) so as the prop moves across, each successive line scan catches a lower portion of the prop so you get a horizontal line gradually decending from right to left, blank space, then the other side of the prop comes along and you get the 2nd slanted line. If you got 4 lines then your phone captured each half of the prop twice as it swung into view.

wdross Loc: Castle Rock, Colorado

sloscheider wrote:

Lets say the 1st half of the prop comes along coun... (show quote)

Excellent job of explaining this electronic shutter artifact (aka: "rolling" shutter).

wdross Loc: Castle Rock, Colorado

billgdyoung wrote:

this image was taken with iPhone... don't know the f-stop, shutter speed, ISO... just shot thru the wind shield. Why the horizontal lines? Something to do with the way the phone's shutter or sensor scans?

Also, go into your shutter data on your iPhone. From what you have given us, I suspect the shutter speed is between 1/300 and 1/400 (based on the picture and RPM, ~1/360).

sloscheider Loc: Minnesota

wdross wrote:

Also, go into your shutter data on your iPhone. From what you have given us, I suspect the shutter speed is between 1/300 and 1/400 (based on the picture and RPM, ~1/360).

I’m curious too, though I was thinking about 1/600 or maybe a bit faster. I count about 7 or 8 passes so 3 to 4 full rotations (assuming a 2 blade propeller).

Shutterbug57

bkyser wrote:

Easy peasy....If you don't want to answer a question, then move on to the next thread.
Places like UHH are made specifically for people to ask and answer questions. Maybe it's you that should be somewhere else.
Were you never a beginner? Why do you come here, other than to belittle people who come for knowledge?

So, if someone at the FBO tells you of a particular NOTAM, do you ask them to read it to you?

wdross Loc: Castle Rock, Colorado

sloscheider wrote:

I’m curious too, though I was thinking about 1/600 or maybe a bit faster. I count about 7 or 8 passes so 3 to 4 full rotations (assuming a 2 blade propeller).

Darn, forgot that the plane is not twirling a maple seed. I stand corrected. You are right that the speed is faster. Probably between 1/600 (as you indicated) and 1/800.

bkyser Loc: Fly over country in Indiana

Shutterbug57 wrote:

So, if someone at the FBO tells you of a particular NOTAM, do you ask them to read it to you?

Big difference, not even close. Google may actually direct someone to UHH for photography answers. You have to know how to read a NOTAM to get your drone or pilot's license. Apples and oranges.

If you get your butt hurt because someone calls you out for picking on someone who goes to a PHOTOGRAPHY FORUM for photography answers, uh.... You may want to re examine what a photography forum is for.

Shutterbug57

bkyser wrote:

Big difference, not even close. Google may actually direct someone to UHH for photography answers. You have to know how to read a NOTAM to get your drone or pilot's license. Apples and oranges.

If you get your butt hurt because someone calls you out for picking on someone who goes to a PHOTOGRAPHY FORUM for photography answers, uh.... You may want to re examine what a photography forum is for.

The point was that you did not read the response. The poster answered your question. If you wan5 answers on a forum, you might try reading what is posted.

bkyser Loc: Fly over country in Indiana

Shutterbug57 wrote:

The point was that you did not read the response. The poster answered your question. If you wan5 answers on a forum, you might try reading what is posted.

I did read the responses, and many were good and helpful. The ones that are uncalled for are "google it" and the like. They went to a PHOTOGRAPHY FORUM, to ask a PHOTOGRAPHY question. A better analogy is going to a general practitioner, to treat a rare form of brain cancer. in our happy little example, Google is the general practitioner, and the photography forum is the specialist.

Before you say that you get a lot of misinformation here......uh.......how much information is 100% correct on google?

Just really tired of people thinking that they are in charge of what questions are worthy, and which ones aren't.