Bird distance

[aloksinha2001]

Team,

I need some help from experienced folks here.

There are many ways to ask the same question, so I will try to ask in as many ways as possible.
Question 1:
Bird = 12", Lens = 300mm
    What needs to be my subject distance to fill the frame.

Question 2: What is the maximum usable (usable defined as sharp photo), assuming good light, stability, aperture etc) subject distance for a good bird (12" or 24") photo.

Question 3: I have 12' bird perched @ a distance of 200 feet, will a typical 300mm give a sharp image for the same.

Layman Question: All above questions point to the same question - with a lens of 300mm, what is the maximum distance that a medium size bird can be shot and beyond what distance should it be just ignored.

Any pointers...

Alok

[kshitij]

Hi alok,

A 12inch bird should be aprox 8 to 10 feet to fill the frame.

You should get tack sharp shots of a 12inch bird till a distance of aprox. 20 to 30 feet. Distance could be aprox twice for a 24inch height bird.

for 200 feet you could use a 1.4x on a f4 and 2x on a f2.8 300mm lens to get a decent shot.

The above replies are based on my experience with the canon 300 f4l.

[krishnanv]

Team,

I need some help from experienced folks here.

There are many ways to ask the same question, so I will try to ask in as many ways as possible.
Question 1:
Bird = 12", Lens = 300mm
    What needs to be my subject distance to fill the frame.

Question 2: What is the maximum usable (usable defined as sharp photo), assuming good light, stability, aperture etc) subject distance for a good bird (12" or 24") photo.

Question 3: I have 12' bird perched @ a distance of 200 feet, will a typical 300mm give a sharp image for the same.

Layman Question: All above questions point to the same question - with a lens of 300mm, what is the maximum distance that a medium size bird can be shot and beyond what distance should it be just ignored.

Any pointers...

Alok

Ans 1: Nikon 300mm F4 has an angle of view  = 8°10' [5°20' with Nikon digital cameras (Nikon DX format)]

         To fill the DX frame edge to edge, the subject needs to be at 10.7 feet

Ans 2: Approx inside of 20 feet is great but, one could frame the surroundings interestingly and get shots even further away. Smaller the bird, nearer you need to be.

Ans 3: Yes given good light, no haze and atmospherics, good technique, yes its very possible. But the birdie will be small in the frame.

You have the option of observing the bird and setting up at a place where you are hidden and closer to the bird. But, this takes some patience and field craft.

best regards
http://www.shootyourvision.com
http://www.facebook.com/krishphoto

[rajib]

1. Distance from Object = Focal Length x (Actual Height of Object / Height of Object on Sensor)
hence d = 300 mm x (304.8 mm / 15.6 mm) {bird 12" high = 304.8mm, APS-C Sensor height = 15.6mm}
d = 5861.53mm = 19.2 feet

More at: http://www.rajib.com/going-to-forest-safari-what-zoom-lens-should-i-take/824/

2. Sharp Print: technically, there are 2 points of consideration

a. Number of pixels required to print a 24" photo: Assuming, that the photo follows 3:2 ratio, hence the photo is 16" x 24". Assuming printing is done at 300 dpi (90K dots per Sq. In.). Hence Total number of dots = 16 x 24 x 90000 = 34,560,000. If each dot is represented as pixel, the image requires a 34 MP camera. In real-world however, interpolation can save the day and you should be able to generate a pin-sharp print from a 16-18 MP camera.

b. Distance, Focal Length, Optic Quality: These vary very widely. For ex: If you only have access to a 18-55mm lens, you will need to get quite close to the subject to obtain a Full-Sensor image. Even if you use a 70-300mm lens, the optics are likely to perform poorly at the extreme ends of the lens capability. i.e. your lens may give better images at 200mm focal length than at 300mm. Optic quality is subject to the glass used and also the general shooting conditions (haze, dust, wind etc.).

3. Question #3 is similar to #1 & #2 and I hope has been answered to your satisfaction.

HTH

[aloksinha2001]

Ok this is serious maths - need to look at it when I am not drunk... let me try to understand tomorrow and then I would respond 

Alok

1. Distance from Object = Focal Length x (Actual Height of Object / Height of Object on Sensor)
hence d = 300 mm x (304.8 mm / 15.6 mm) {bird 12" high = 304.8mm, APS-C Sensor height = 15.6mm}
d = 5861.53mm = 19.2 feet

More at: http://www.rajib.com/going-to-forest-safari-what-zoom-lens-should-i-take/824/

2. Sharp Print: technically, there are 2 points of consideration

a. Number of pixels required to print a 24" photo: Assuming, that the photo follows 3:2 ratio, hence the photo is 16" x 24". Assuming printing is done at 300 dpi (90K dots per Sq. In.). Hence Total number of dots = 16 x 24 x 90000 = 34,560,000. If each dot is represented as pixel, the image requires a 34 MP camera. In real-world however, interpolation can save the day and you should be able to generate a pin-sharp print from a 16-18 MP camera.

b. Distance, Focal Length, Optic Quality: These vary very widely. For ex: If you only have access to a 18-55mm lens, you will need to get quite close to the subject to obtain a Full-Sensor image. Even if you use a 70-300mm lens, the optics are likely to perform poorly at the extreme ends of the lens capability. i.e. your lens may give better images at 200mm focal length than at 300mm. Optic quality is subject to the glass used and also the general shooting conditions (haze, dust, wind etc.).

3. Question #3 is similar to #1 & #2 and I hope has been answered to your satisfaction.

HTH

[Hellwrath]

1. Distance from Object = Focal Length x (Actual Height of Object / Height of Object on Sensor)
hence d = 300 mm x (304.8 mm / 15.6 mm) {bird 12" high = 304.8mm, APS-C Sensor height = 15.6mm}
d = 5861.53mm = 19.2 feet

More at: http://www.rajib.com/going-to-forest-safari-what-zoom-lens-should-i-take/824/

2. Sharp Print: technically, there are 2 points of consideration

a. Number of pixels required to print a 24" photo: Assuming, that the photo follows 3:2 ratio, hence the photo is 16" x 24". Assuming printing is done at 300 dpi (90K dots per Sq. In.). Hence Total number of dots = 16 x 24 x 90000 = 34,560,000. If each dot is represented as pixel, the image requires a 34 MP camera. In real-world however, interpolation can save the day and you should be able to generate a pin-sharp print from a 16-18 MP camera.

b. Distance, Focal Length, Optic Quality: These vary very widely. For ex: If you only have access to a 18-55mm lens, you will need to get quite close to the subject to obtain a Full-Sensor image. Even if you use a 70-300mm lens, the optics are likely to perform poorly at the extreme ends of the lens capability. i.e. your lens may give better images at 200mm focal length than at 300mm. Optic quality is subject to the glass used and also the general shooting conditions (haze, dust, wind etc.).

3. Question #3 is similar to #1 & #2 and I hope has been answered to your satisfaction.

HTH

Thanks a lot Rajib, now I can make calculations for different types of birds if I plan to go birding.

[krishnanv]

Well, not that difficult actually with all the online resources available.

http://www.handymath.com/cgi-bin/arc18.cgi?submit=Entry

Try this online arc calculator :-)

You know the Angle, you know the width, plugin the numbers and get the value for the Radius & Apothem  which is the distance to the subject :-)

Better still , grab a soft toy ( simulates the features / fur ) and try at various distances .
http://imaging.nikon.com/lineup/lens/simulator/index.htm

best
---Krishnan

http://www.shootyourvision.com
http://www.facebook.com/krishphoto

Ok this is serious maths - need to look at it when I am not drunk... let me try to understand tomorrow and then I would respond 

Alok

1. Distance from Object = Focal Length x (Actual Height of Object / Height of Object on Sensor)
hence d = 300 mm x (304.8 mm / 15.6 mm) {bird 12" high = 304.8mm, APS-C Sensor height = 15.6mm}
d = 5861.53mm = 19.2 feet

More at: http://www.rajib.com/going-to-forest-safari-what-zoom-lens-should-i-take/824/

2. Sharp Print: technically, there are 2 points of consideration

a. Number of pixels required to print a 24" photo: Assuming, that the photo follows 3:2 ratio, hence the photo is 16" x 24". Assuming printing is done at 300 dpi (90K dots per Sq. In.). Hence Total number of dots = 16 x 24 x 90000 = 34,560,000. If each dot is represented as pixel, the image requires a 34 MP camera. In real-world however, interpolation can save the day and you should be able to generate a pin-sharp print from a 16-18 MP camera.

b. Distance, Focal Length, Optic Quality: These vary very widely. For ex: If you only have access to a 18-55mm lens, you will need to get quite close to the subject to obtain a Full-Sensor image. Even if you use a 70-300mm lens, the optics are likely to perform poorly at the extreme ends of the lens capability. i.e. your lens may give better images at 200mm focal length than at 300mm. Optic quality is subject to the glass used and also the general shooting conditions (haze, dust, wind etc.).

3. Question #3 is similar to #1 & #2 and I hope has been answered to your satisfaction.

HTH

[SRoy]

In my humble opinion it is better to learn these things about bird photography from the field and by staying as far away as possible from mathematics. Because mathematics will presume the bird is either vertical or horizontally placed and do the calculation. The bird in reality might be neither but diagonal or sometimes a third of all three (for example a purple heron with its neck stretched out will have some part of its body vertical, some horizontal and some diagonal ;-). The possibilities are actually endless.

Once you get to the field, you will soon realise that it is possible to get closer than 200 feet to many birds if you adopt the right technique and like the purple heron there are many birds that are more than 12 inches long (I am sure you used the 12 inches figure just to understand the concept).

Also, another unsolicited advice - tack sharp portraits of birds is quite boring beyond a point. But I agree that there is always a desire a get to that point first :-)

The 300 prime of either Canon or Nikon is a brilliant birding lens. Don't spoil it with a TC.

[amitk26]

In my humble opinion it is better to learn these things about bird photography from the field and by staying as far away as possible from mathematics. Because mathematics will presume the bird is either vertical or horizontally placed and do the calculation. The bird in reality might be neither but diagonal or sometimes a third of all three (for example a purple heron with its neck stretched out will have some part of its body vertical, some horizontal and some diagonal ;-). The possibilities are actually endless.

Trying not to be a prick but I don't see why mathematics should fail in any case , Rajib is just trying to  give an estimate on what size of object can fill a 15.6 mm sensor from what distance. You need to have this estimate before hand unless you have a fortune to buy different focal lengths and  no other job at hand rather then going to nature parks and trying them out.

Mathematics does not spoil any of these possibilities in any case simple application of trigonometry  and lens formula
with different set of numbers is required , for example a 12 inch  bird sitting on a flat branch along the diagonal is likely to be 8 inch high and its' projection  on the horizontal axis will be roughly 9 inch.  ( unless bird is little skewed and is 8.9 inch high and cast a projection of 8 inch on ground while sitting at 45 degrees) , 

so d = 300X ( 8*25) / 15.6 = 3846 mm or 12.6 feet.  ( 1 inch == 25mm)

You can extend this to 3 dimensional plane as well.

[aloksinha2001]

In my humble opinion it is better to learn these things about bird photography from the field and by staying as far away as possible from mathematics. Because mathematics will presume the bird is either vertical or horizontally placed and do the calculation. The bird in reality might be neither but diagonal or sometimes a third of all three (for example a purple heron with its neck stretched out will have some part of its body vertical, some horizontal and some diagonal ;-). The possibilities are actually endless.

Once you get to the field, you will soon realise that it is possible to get closer than 200 feet to many birds if you adopt the right technique and like the purple heron there are many birds that are more than 12 inches long (I am sure you used the 12 inches figure just to understand the concept).

Also, another unsolicited advice - tack sharp portraits of birds is quite boring beyond a point. But I agree that there is always a desire a get to that point first :-)

The 300 prime of either Canon or Nikon is a brilliant birding lens. Don't spoil it with a TC.

The objective of asking for maths is NOT to make great photographs, based on calculator every time. It is to re-affirm, what I am seeing in my pictures.

I was beating up myself not able to catch eagles flying at a distance of 350' to 400' from where I was... What was causing this grave concern was, I could read clearly - with the 300mm a car number plate (at 1:1 zoom) at a distance of 500-600ft, but was not getting sharp tack image at 350-400. Now knowing now that the 300mm is not at fault is a relief.

Also, sharp tack photos being boring - yes perhaps, I would reach that stage sometime. As a photographer (in each of the field - portrait, landscape, macro, birding etc etc) I have come from a stage of technically illiterate to getting closer to technically literate.
Once that stage is done, I guess the bigger mountain to climb is to go beyond science into art. I guess I have a long way to reach there, so the numbers really work for me

Alok

[SRoy]

I am the last person to rubbish mathematics. What I tried to hint (jokingly) is that in wild life photography where the situation changes every moment - real life teaches you a lot more than calculators. So time is better spent in the field with the camera than the calculator at home. The whole sentence was said more in jest than out of any contempt for mathematics. It's good to have the mathematical basics at the back of your head while shooting.
With overhead flying birds there isn't much that you can do to get closer, unless you follow the "open secret" tactics of some of the controversial nature photographers who use live baits like snakes, rats, fish etc for those super close ups of raptors. shhhhhhhhhh. Don't mention that I said this.

By the way 300/400 feet is far too long for a 300 tele. If you see a birder taking such shots it is most likely for identification purposes and not for sharing. What focusing mode did you use for the BIF? That's critical. Also, in the absence of any reference point estimating the distance of an overhead BIF is not easy at all.

Another important thing to remember, the sharpness required to make a number plate look really sharp and readable is virtually nothing compared to what is required to make a bird image look sharp. In a bird image the features are really minute and to capture those minute details sharp is not easy, particularly in a flying bird.

Meanwhile, here is a bird in flight for you. An Asian Open Bill.

[Himadri]

Fantastic discussion, terrific inputs. Loved the way things got explained here.

Once that stage is done, I guess the bigger mountain to climb is to go beyond science into art.
Alok

This is the best realization, loved your thought process.

[wild007]

I feel myself lucky enough if I can reach within 30ft!!!

[aloksinha2001]

Fantastic discussion, terrific inputs. Loved the way things got explained here.

Once that stage is done, I guess the bigger mountain to climb is to go beyond science into art.
Alok

This is the best realization, loved your thought process.

No quite honestly, even for the basic techniques in one field - just when you think, you have learnt all the techniques in this field - you read/see/hear about things that someone has done that is so mind boggling that it leaves you grossly humbled.

Alok