Nicolae

Hello,
Could you recommend the type of camera and the process I need to use to take high resolution pictures of a composite material surface (fiberglass, carbon fiber) from a distance of approximately 400 ft. This is for preventive maintenance and quality control purposes. The picture quality should be similar to the pictures taken from (3-4) feet away from the surface. If possible could you recommend a book or technical articles written on this subject.
Thank you very much for your help,
Nick

MT Shooter Loc: Montana

You will need a VERY expensive lens. I recommend a 600mm F4, or an 800mm F5.6 on a very high quality Crop sensor camera body to get the resolution you are seeking.

oldtigger Loc: Roanoke Virginia-USA

how many million are you prepared to pay?
How much accuracy do you need? .1"? .oo1 inch?
Would be much cheaper to use laser.

Nicolae

Thank you very much for your quick reply. Now I need to learn more about these lenses and cameras.

Nicolae

Millions? is out of the question. This must be a joke.

oldtigger Loc: Roanoke Virginia-USA

no joke, how much resolution do you need?
Are you looking for gell cracks, surface ablation or manhole cover size holes?
What do you use at 4 feet now?

Nicolae

I am interested to find out more about the laser technology. Could you recommend a good book or technical article? The intent is to preventatively discover small cracks. A resolution of 0.001 in would be ideal, but I can settle for 0.01 in.
Thank you,
Nick

Nicolae

Somebody suggested using a small quad UAV. I doubt they will provide the quality of imagery we need for an accurate analysis. Any input on that?
Thank you,
Nick

oldtigger Loc: Roanoke Virginia-USA

the bottom line is:
you want a 2:1 macro lens with a 400 foot working distance.
No way baby.
Borrow a 12" celestron telescope with camera adapter and see if that meets your needs.
Your problem will be air currents and a half ton base to hold it steady.

SonyA580 Loc: FL in the winter & MN in the summer

Why in the world are you looking for small cracks from 400' away?

jethro779 Loc: Tucson, AZ

Chernobyl????

NormanHarley Loc: Colorado

Took a shot of the old log house for you because I know about how far it is from my front door because of a survey I have. The distance is 375 feet, give or take a few, fairly close to the 400 you were asking about. The green in the upper left of the picture are some out of focus leaves from a tree. The window is 4 feet by 4 feet to give you an idea of perspective in the shot. I used a 500mm lens with a 1.7 teleconverter to give me an 850mm lens equivalent, then used that on my crop sensor camera to give a final equivalent of 1275mm... If I did my math correctly... I also shot this picture in the shade, which further diminishes my final product because I imagine not all of your shots will be in direct sunlight. Light makes a huge difference. My camera and lens were mounted on my sturdiest tripod, which you will need at this focal length. I also used a timer to reduce vibration, making sure there was no camera movement. The second picture is a crop of the first picture, just the bottom right hand corner of the window. It loses a lot of detail when enlarged this much.
A drone with a camera sounds a lot better! And probably more fun and cheaper.

(Download)


(Download)

oldtigger Loc: Roanoke Virginia-USA

canon made a Canon EF 1200mm f/5.6L USM Lens which is now discontinued.
You can find them used for $120,000.
http://www.the-digital-picture.com/Reviews/Canon-EF-1200mm-f-5.6-L-USM-Lens-Review.aspx

An 11" celestron could be had for $4000.

mtbear

A polarized light source used with a polarizing filter can be use to show stress in fiberglass with proper adjustment but it won't be effective at 400 feet. Might be made to work with a drone though. It really doesn't show cracks as much as stress patterns that might lead to cracks.

NormanHarley Loc: Colorado

Now I want one! Does it come with a Sherpa?