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[Jon Betz]

Lenses for wildlife

Lenses for wildlife

With all this talk of lenses, I thought I'd pose a question. My apologies in advance if this is too basic or perhaps not the best place for this post.

I am looking to purchase a camera to film wildlife (I am a recent college graduate just starting my career). I obviously would benefit greatly from interchangeable lenses, and so I have had my eye on the Red Scarlets for a while. The only problem is, I am unsure about which lenses would be best for wildlife filming. I have been using a Sony FX1, but have been very limited by the 12x zoom. Can someone give me some advice, or point me to some resources that might explain the correlation between mm and magnification, and also might advise which sizes (and even lens mounts) might be best for wildlife filming. Can anyone confirm that the Scarlet would be a good choice for wildlife film? It seems like it will be an amazing and portable camera, but as I said I am somewhat of a beginner and am not sure how to invest in a first good camera.

Cheers

 

[Denis Buhot]

lenses for wildlife shooting

lenses for wildlife shooting

you will find very useful and practical informations in steve Gibby's posts.

As for my personal experience, I need a wide angle (I myself own nikon, 2.8, 17-35mm), a medium range zoom (2.8, 120-300mm sigma), and a very big zoom (5.6, 300-800mm sigma "sigmonster"). Two still lenses : canon, 4.5, 600mm and nikon 2.8, 180mm). Zoom lenses are a must : just finding a fast moving subject kind be a problem when it comes to still lenses over 200 mm... With a zoom, you can zoom down and up again in one second.

All of them give terrific results, given proper light conditions. 4K will offer what was inconceivable before : wide, natural frame (not zoo picture looking) yet retaining amazing details. Sigma may seem second choice brand, but the truth is that you'll find no other lens with specifications like these, and standing shoulder to shoulder with the best primes (beware of possible lemons, though...)

I'm based in Europe, fauna is shy there. Sigmonster might be overkill if you plan to film in Alaska or Africa.

Don't forget you'll need an aperture ring or use a birger mount.

Choose big apertures... the mysterium is rated 320 iso only, the fauna prefers dawn and sunset, and the heat shimmer is much less then...

Don't forget a sturdy tripod...

Consider the weight of the whole setup... You will have to add some lens support device, and at least 6 battery packs per day, since the red one boot-up time is an eternity, and there is no sleep-mode function. If you travel by car in Africa, no problem. If you have to hike your way through adverse terrain, well... you'd better lift weight, or choose some other camera !

Hope that helps

 

[Jon Betz]

Magnification/field of view issues with different sensors and lenses

Magnification/field of view issues with different sensors and lenses

The magnification/field of view issue seems to be confusing others as well as myself, so I hope this post may stir up some answers/clarification. I am interested in the 2/3" Scarlet, so my calculations will use this sensor.

After doing some research online, this is what I have learned regarding lenses and image cropping. The 2/3" Scarlet sensor is smaller (10.1mm x 5.35mm) than the 35mm frame area (36mm x 24mm). Thus, when a 35mm lens projects an image onto the Red sensor, only the central portion of the image is captured (because the image is much larger than the sensor). This seems like it provides at least one advantage: lenses designed for 35mm cameras effectively act like more expensive lenses because you are only using the "sweet spot" of the lens elements. But that aside, it also seems that 35mm lenses would provide higher magnification on a Scarlet (I'm not sure if magnification is the right word, but it seems like the subjects would be larger in the frame).

Regarding the magnitude of cropping: to determine the magnitude of the cropping effect, just compare the diagonal measurements of the 35mm frame to the Red sensor. The 35mm diagonal is 43.27mm, and the Scarlet diagonal is 11.43mm. Dividing these gives a ratio of 3.79, indicating that a 100mm lens (designed for a 35mm camera) used on a Red Scarlet will provide the same field of view as a 379mm lens on a 35mm camera. It seems like this would be a great advantage. For instance, it seems like if I am looking for the field of view of a 300 or 400mm lens to film wildlife, I only need to really find an 80 or 100mm 35mm lens to use with the Red. Is this cropping truly an advantage, providing closer views of distant objects when using standard 35mm lenses, or is it a disadvantage somehow (in terms of image quality or something else I am missing)?

Also, It seems like focal length is often used as a short-hand for field of view, but this is assuming we are talking about 35mm still focal lengths, right?

If these question would be better placed in another thread, can someone point me in that direction? Cheers.

 

[Jeff Kilgroe]

Also, It seems like focal length is often used as a short-hand for field of view, but this is assuming we are talking about 35mm still focal lengths, right?

This is a common misconception around here and throughout the industry. :angry:

Focal lengths are based on millimeters as a standard and a focal length remains constant, no matter what format you are shooting. So a 12mm lens produces the same angle of view (AOV), whether it's a 12mm lens designed for 35mm cinema, full frame 35mm photography, or 2/3" HD. a 12mm lens is a 12mm lens, a 50mm lens is a 50mm lens and so on...

What does change is the field of view (FOV) and it is determined, mostly, by two factors. One is the format you are shooting to (S35, FF35, 2/3", etc..). A larger image area, film plane or sensor will yield a larger FOV at any given focal length than a smaller image area will. The other factor that determines FOV is lens design and construction. A lens can be made with larger elements and mounts to allow for a larger image circle or greater coverage at a given focal length. Therefore a 12mm lens designed for 35mm cinema will, generally speaking, be larger than a 12mm lens designed for 2/3" video.

So, if you take a 12mm S35 lens and put it on a 2/3" sensor, you will see about a 54 degree FOV. That same lens would be about 109 degrees FOV on S35 format. OTOH, if you took a 12mm lens designed for 2/3" or 16mm, it would still give the 54 degree FOV on its intended format, but when placed on a S35 camera, it would not cover the entire area. It would still give the exact same AOV as the S35 lens mentioned above, but it's not designed to cover the larger format, so it's FOV would be restricted in that it would start to vignette and probably not cover the entire frame.

With smaller image areas, it takes relatively shorter focal lengths to deliver wider FOVs than with larger image areas. That is why when you look at 2/3" or 16mm lenses, they tend to have shorter focal lengths like 9mm on the wide end of a standard kit vs. the 18mm on the wide end of a S35 kit.

 

[Jon Betz]

This all makes sense, but still begs the question, is this cropping effect (using 35mm still lenses on a smaller DSLR/DMSLR sensor) an advantage or a disadvantage? In my understanding, it is an advantage for me because it would allow me to capture images of subjects that fill the frame where they would appear smaller if I used the same lens on a 35mm camera. In other words, it seems like I would be getting more magnification for the money. I am wondering, however, whether this is indeed the case. Are there any problems with cropping or is it really an advantage as I have explained it?

 

[Jeff Kilgroe]

It's neither an advantage or disadvantage. It just is what it is. Larger 35mm format lenses are typically bigger physically and cost more money. It's true that you are using the "sweet spot" of the lens in some respects, when you only capture the center of the image that gets projected onto the image plane. OTOH, 16mm and 2/3" glass doesn't lose sharpness from center to edge to the same degree because of the smaller elements in relation to focal length and these smaller lenses can often carry a higher overall MTF rating. Many newer lenses or most current lens designs in general, have much more even illumination and sharpness into the corners, this is not as big a concern as it was with glass a few years ago.

IMO, if you only want to shoot in a 2/3" format, you won't be doing yourself any favors by trying to shoot with 35mm format glass in most cases. You will be lacking the wider focal lengths that you may often desire and gaining nothing over shooting the larger 35mm format to begin with and simply cropping out the desired area of the image. In that respect, you don't get more magnification for the money. Or at least the lenses themselves don't provide that. It seems that 2/3" Scarlet will have more pixels or photosites within the 2/3" area compared to S35 Scarlet or EPIC within their 2/3" cropped area. So you may get a little more magnification for your money in that way. But there could be other trade-offs to gain that higher pixel density at that size; like less sensitivity (slower ISO rating). But at this time, we don't have all the specs, so this is just conjecture at best when comparing the upcoming cameras.

 

[Jon Betz]

Thanks Jeff. I think we are on the same page. I guess it's just a bit frustrating that many people recommend 300 or 400mm lenses (35mm) for filming wildlife, but then I don't really know which 2/3" or 16mm lenses correspond to these 35mm focal lengths. It would be easier if everyone just referred to FOV.

 

[Jeff Kilgroe]

First off, don't think of them as "35mm focal lengths". You'll just end up confusing yourself or others you work with if you say things like "35mm focal lengths". If someone says they shot something with a 300mm, then you can ask them what camera or format. 300mm lenses are available on various formats, not just 35mm. And they always produce the same viewable angle per mm regardless of whether they're on a 35mm camera or a 2/3" camera or whatever.

Best way to look at it is with a cheat sheet or conversion table. There are a number of conversion charts out there, some free, some not. As well as just simple math (simple trigonometry that is) that will tell you the FOV based on the focal length and format size. Try to avoid referencing or buying into "crop factors" terminology that a lot of people like to use. Crop factors are relative and I see so many people talk about crop factors here and they use them incorrectly. They also rely on a frame of reference, such as RED One 4K is roughly a 1.7X, in regards to frame width, from a FF35 sensor. But to go around saying that RED One 4K has a 1.7X crop factor makes little sense to anyone other than someone who is familiar with shooting FF35 most of the time.

The actual math to calculate your angle of view can be referenced here.

Best thing to do is just make table that has Focal length in mm horizontally across the top and common formats like FF35, S35, 2/3", etc.. in the left vertical column. Then all you have to do is if you're shooting 2/3" and want a 27 degree AOV, you can reference 27 degrees in the 2/3" row and follow the the column up to the top to see what focal length you need.

 

[Tim Whitcomb]

First off, don't think of them as "35mm focal lengths". You'll just end up confusing yourself or others you work with if you say things like "35mm focal lengths". If someone says they shot something with a 300mm, then you can ask them what camera or format. 300mm lenses are available on various formats, not just 35mm. And they always produce the same viewable angle per mm regardless of whether they're on a 35mm camera or a 2/3" camera or whatever.

Best way to look at it is with a cheat sheet or conversion table. There are a number of conversion charts out there, some free, some not. As well as just simple math (simple trigonometry that is) that will tell you the FOV based on the focal length and format size. Try to avoid referencing or buying into "crop factors" terminology that a lot of people like to use. Crop factors are relative and I see so many people talk about crop factors here and they use them incorrectly. They also rely on a frame of reference, such as RED One 4K is roughly a 1.7X, in regards to frame width, from a FF35 sensor. But to go around saying that RED One 4K has a 1.7X crop factor makes little sense to anyone other than someone who is familiar with shooting FF35 most of the time.

The actual math to calculate your angle of view can be referenced here.

Best thing to do is just make table that has Focal length in mm horizontally across the top and common formats like FF35, S35, 2/3", etc.. in the left vertical column. Then all you have to do is if you're shooting 2/3" and want a 27 degree AOV, you can reference 27 degrees in the 2/3" row and follow the the column up to the top to see what focal length you need.

Jeff- could you be more specific? :sarcasm:

Seriously. thank you for sharing all this excellent information. I for one appreciate the detail and clarity. Helps a ton in determining lenses
and sensors.

cheers

 

[Jon Betz]

Thanks for the help. As you can tell I am new to this and am just trying to break into the industry with as much knowledge of this stuff as possible. I feel much more comfortable with all of this now, although I know there will always be more to learn.

 

[Jeff Kilgroe]

As a correction to what I posted above, since I know some pedantic perfectionist will eventually try to correct me.... I hastily typed the "crop factor" for RED One 4K and just used a general approximate. It is actually 0.614X the width of FF35, which means that FF35 is 1.627X wider than R1 4K, not 1.7X as I had typed.

 

[Michael Moreno]

Lookout Jeff i just saw a pedantic perfectionist running naked
from thread to thread on the forum :yikes: