D2X with 300mm f/2.8 or 400mm f/2.8

Discussion in 'Nikon' started by neil_lupin, Oct 30, 2007.

  1. Please help!

    I'm photographing the Eagles in London tomorrow night. Shooting from the mixing
    desk about 50 feet back from the stage with a D2X (therefore 1.5x sensor).

    Don't own anything bigger than a 70-200mm so will hire either a 300mm f/2.8 or
    400mm f/2.8 (although aren't they a bit soft wide open?). Or do I risk the
    Sigma 500mm f/4.5 which is slower but still a cracker of a lens? (all 3 are
    available from the hire firm and no, I can't hire two or three of them, only 1!)

    Question - from 50 feet if I want (portrait mode) to take shots of individual
    performers from head to knees, (ie about 4-5 foot of height for sake of
    argument), how did I calculate the focal length I need?

    I want to avoid using the 2x crop in camera if possible, but appreciate I may
    have no choice. Will use the 70-200 for some group landscape shots.

    Cheers, Neil
    www.neillupin.com
     
  2. -- "how did I calculate the focal length I need?"

    Angle of view needed:

    Angle = 2 * arcsin((5ft / 50ft) / 2) = 5.74deg

    Focal length needed:

    FL = 24mm / (2 * tan(5.74 / 2)) = 240mm

    so, your 200mm lens should do an excellent job for this.

    (I took 24mm as framesize, since you wanted portrait mode).
     
  3. Rainer, thank you. I don't understand that calculation in the slightest, but it works for me! Neil
     
  4. The first fomula is the sinus function applied to your numbers, the latter is the projection formula for rectilinear lenses ... but I just saw something very obvious ...

    there is a relation of framesize (24mm) and required focal length (240mm) being 1:10 ... and another one ... objectsize (5ft) and object distance (50ft) also being 1:10 ... and indeed , for small angles or for relatively small relations of objectsize/objectdistance ... say from 1/3 on ... you can skip all these strange formula stuff and simply calculate:

    FocalLength = FrameSize * ObjectDistance / ObjectSize

    FL = 24mm * 50ft / 5ft = 240mm

    The error made by skipping the complicated part is still less than 10 percent at a size to distance ratio of 1:2.
     
  5. That is a useful simplification, Rainer. Thank you!
     
  6. ShunCheung

    ShunCheung Administrator

    I suggest you do some test shots from 50 feet and judge the coverage carefully. The key to this whole thing is whether you are indeed 50 feet from the stage or not. If you are off by a lot, it really changes everything. Additionally, how big is that stage? Does it make a big difference from the person closest to you and the one farthest from you? I shot the attached image with exactly a D2X and a 70-200mm AF-S at 200mm, from approximately 50 feet away. It is the entire frame with no cropping. That girl happens to be quite tall for a womon; she is probably 5'9" or so. Therefore, maybe the 70-200mm is sufficient already. A 400mm will cover 25% of the 200mm area, as indicated by the red rectangle. I also have the 300mm/f2.8 AF-S, 1st generation, not the current VR one. It is very sharp wide open at f2.8. I wouldn't hesitate using that at all. I have no experience with any 400mm/f2.8, but they are big and heavy.
    00N88k-39432884.jpg
     
  7. Thanks guys. I won't have an opportunity to test out whether it really is 50 feet or not before I step up to the mixing desk seconds before they come on stage. I've spoken to the venue and they reckon its 45 feet to the front of the stage (14-15 seat rows) so I'm taking 50 maybe 55 feet as being most likely. Judging by that test shot Shun (thanks for that) I think I'll go with the 300mm and use the in camera crop if I'm really coming up short. The 70-200 at 70mm or so ought to get me all four performers but I'll take a 28-70 as well just in case I want a really wide shot or two showing the whole stage, house lights etc. I hate shooting from mixing desks - vowed last time I'd never do it again, but this is a one off opportunity - I doubt the Eagles will ever play such a small venue (2300 people) again in England - plus if you've read about the controversy surrounding this one, tickets are ?1000 each!!! (I don't have one!) Cheers, Neil
     
  8. ShunCheung

    ShunCheung Administrator

    Neil, I was suggesting that maybe you can put a, say, 6 foot mark on a tree or wall near your home or office and check out the coverage for 200mm from about 50 feet away. It would be even better if you can find a temporary model.

    You might not even need a 300mm/f2.8, but it is better to have some margain for error on both ends. You'll need good support for the 300mm/f2.8 and a TC-14E will be handy also.
     
  9. <...I'll take a 28-70 as well just in case I want a really wide shot or two showing the whole stage, house lights etc.> I doubt that the wide end (28mm = 46 degree horizontal Angle of View on DX format) will be wide enough for that coverage from 50'...I could be wrong but a 20 or 24mm is cheap insurance to get it all.
     
  10. I suggest hiring the Nikon TC14E as well as the 300 if you can get it! that'll give you a 420mm f4 with very little loss in quality. Between your own 70-200, the 300f2.8 and 420 f4 you should really be covered...those TCs are really designed for those lenses.
     
  11. with the 300 it will be 450 on the d2x?
     
  12. ShunCheung

    ShunCheung Administrator

    with the 300 it will be 450 on the d2x?
    No, the focal length of a lens is a characteristic of that lens. It does not change regardless which camera body you put behind it.
     
  13. Shun Cheung, you are correct but if we are 100 feet from a given subject and I am looking
    at the images you made with your DX camera with 200mm and want to get the same angle
    of view on my full frame (D3) 24x36 sized camera I would need a 300mm.

    again you are correct but in this context I think people are speaking of angle of view,
    where the "crop factor" will indeed have a similar effect as focal length

    and for the original poster (its past the concert but maybe someone else will find this post
    helpful), I do not think the 400 is an option regardless, there is no way I could maneuver
    my way around an event like that with my 400 and I am 6'3 220 pounds, even the 300
    could get old real fast, I guess for concert shooting the new VR 300 may be worth it.

    If you do get rent a long lens get a soft case (Tenba is a the one I use) that can be worn
    like a back pack it will stink having a 300 or 400 slung over your shoulder from the lens
    strap, even if you have to buy a decent case for the event you can ebay it after and not
    lose to much.

    regards and please post some pictures from teh concert
    Ray
     
  14. ShunCheung

    ShunCheung Administrator

    If you want to discuss the angle of view, please specify that in terms of degrees; that is how angles are measured, not by focal length.
     
  15. "I need to fill the frame with that car at 300 feet, what lens should I use?" my next response
    would be what camera DX, 24x36. medium format......

    regards
    Ray
     

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