AF-P 70-300 question

Discussion in 'Nikon' started by tommarcus, Jun 28, 2020.

  1. its the only lens i have right now for my 7500. It does alright, however the photos i uploaded for my account were all taken with it, and were taken with it maxed out at 300mm. And the animals in question were 20-50 yards away at the time. The rabbit at the stump was perhaps 10 yards, maybe 12.

    Am i simply doing something wrong as i do not seem to get the massive magnification that the nikon website indicates i should... or is it that i am NOT using the crop mode setting?
     
  2. The D7500 is a crop sensor body. There is no DX crop mode on it. I assume there are other crop modes to get different aspect ratios, but those are not the same thing.

    What Nikon web page are you looking at?
     
  3. William Michael

    William Michael Moderator Staff Member

    This question and your other question here LINK show a misunderstanding that you have concerning Lens' Data Sheet term - "Magnification".

    Member 'chulster' has explained in your other thread.

    Further to that explanation, the information you require is "Field of View" and it is easily available from most of the on line Depth of Field Calculators. Using these calculators you can estimate how much of the image a Subject will occupy at any given Distance, for any given Focal Length and Camera Format.

    As an example - in your shot of the Rabbit, assuming the bunny is about 15" long, and you were 30ft away, then you'd need about a 600mm lens on your D7500 to just about fill the frame - on the other hand, assuming the bunny was 15" long I calculate that you were about 16 Yards away for that shot.

    By the way, you didn't nail focus on the bunny, the image's Plane of Sharp focus, is in front of the Rabbit - maybe the reason was because the Centre Point Auto Focus was active - that is a common cause.

    WW

     
  4. going by my photo, i think that the rabbit in question is actually 10-12" tip of nose to tip of tail. The stump makes him look bigger then he is. Its about 12" in diameter.

    i use the manual mode on the dial, AE is ok, but i dont like how it has a default setting to only use f/5 for an aperture. And in manual the camera only gives 1 center focus box to use. I find it better then the 6-8 it gives me in AE mode.
     
  5. Two little things I notice that might want further reading-up, etc.

    If you have been using the green "auto" setting, many areas of control are lost. If you want the convenience of point and shoot exposure control, "P" gives that but allows you to choose things like focus mode, metering pattern, and so forth.

    On a variable-aperture zoom, you should be able to use any aperture you want in A mode as well as M. But if you are using maximum aperture it makes a difference whether you set it when zoomed out or in. If you have a 4-5.6 zoom, for example, and set it to max when zoomed long, it will select 5.6, and when you zoom out it will stay at 5.6, If you set it at max when zoomed out, it will select 4. The variable aperture will then go to 5.6 as you zoom in, but it will return to 4 as you zoom out again. I hope that makes some sense.

    If you are using P mode, you can still vary the aperture. It will only allow settings which satisfy the meter, but within that range, if you use the rear dial, it should choose among them.

    You can set the AF focus point in A,S, and P modes as well, to single point if that's what you like. I think it would be a good idea to study up on all the variations available in both AFS and AFC.

    The D7x00 cameras do have a crop mode, which reduces the field of view further. But it really is just a crop, with no change in the quality of the image. It doesn't really do anything different from cropping in post-processing. On earlier cameras, the smaller image can help stretch the measly shot buffer for continuous shooting, but otherwise it's not that useful except to save a little memory and perhaps to save needing to crop so much in post.
     
  6. I would guess the proportion of users who comprehend this behavior is on the order of five percent.
     
  7. A 300mm lens on a DX camera only provides a 9.6x magnification.
    9.6x is not "massive" magnification.

    As William said, it is about field of view. size of subject vs. distance.
    A small animal (rabbit) at 20 yards needs more magnification than a larger animal at 20 yards (cow).
    And, an animal, like a rabbit at close distance say 5 yards requires much less magnification than at longer distance, say 20 yards where it needs MORE magnification.

    BTW 50 yards is a relatively LONG distance. When I shooting a football player at 50 yards, it requires significant cropping of the image.
     
  8. The two sentences are confusing. Lets try being more specific with numbers.
    If you have a 70-200 f/4-5.6 zoom. Set the lens to 200, then set the aperture to max f/5.6.
    When you zoom long, to 200mm, the aperture is at f/5.6, the second/smaller number.
    When you zoom close to 75mm, the aperture is at f/4, the first/larger number.
    Back and forth.
    This only happens when you are at the max aperture of the lens.
    If you are shooting at f/5.6 or smaller (f/8, 11, 16, etc), there is no change.
     
  9. Also, don't be afraid to crop (after the shot, on the computer), you've got plenty of megapixels to burn for most outputs.

    A tight crop from a shorter, faster lens, sharply focussed, beats a blurred shot from a long slow tele zoom, even if the latter has more pixels on target.

    Though, if you need the reach often, get the longer lens.

    I'll shut up now as wildlife isn't something I do much of and my idea of a long lens tops out at around 135mm.
     
  10. MIstake, Set the lens to 70mm and f/4, not 200
     
  11. To me, moving wildlife is like sports.
    I cannot crop TIGHT in the camera, because that makes it HARDER to track a moving subject.
    I need to have space around the subject to track a moving subject, and the faster/more erratic the movement, the more space I need.
    So for me cropping is SOP.
     
  12. And if you start at 200mm f/5.6 and zoom to 70mm, then as Matthew said (clearly enough), the lens will stay at f/5.6.
     
  13. ... and he requires body armour....:D

    Eh? That makes no sense at all.... unless you haven't found how to unlock it. Rotate the ring around the 4 way jog switch so the dot points to the dot and away from L (for LOCK)

    If you've chosen Single Point AF, yes you get one "Focus Box", but you can move it around the screen. It doesn't need to remain in the centre. You move the AF point with the UP-DOWN-LEFT-RIGHT pad segments. (once unlocked!)

    So for bunny pic, you can retain the composition but move the Single AF Point to cover bunny's eyes.
     
  14. Gary, I think you misunderstood my post, and I'm sorry if it was confusing.

    If you have a variable aperture zoom - let's say one which is F4 at 55 and F 5.6 at 300, this is what happens:

    If you set it to its maximum aperture of F4 at 55, and zoom in, the variable aperture will go to 5.6, and if you zoom back out, it will return to 4.\

    But this does NOT happen if you set it its maximum aperture of 5.6 at 300. If you do this, and then zoom out to 55, the aperture will remain at 5.6. The camera assumes you have set 5.6, not that you have set "maximum aperture." At any focal length, the maximum aperture available for setting will be the largest aperture you get when you zoom.
     
    Gary Naka likes this.
  15. Guys, leave the 'oddity' of a variable aperture zoom alone.

    Obviously the OP needs more straightforward info.
     
  16. I'm reminded of a scene from the Father Ted episode "Hell" in which Father Ted tries to explain to Father Dougal the difference between "small" and "far away", using cows as an example.
     
    mike_halliwell likes this.
  17. Point taken, and it's probably not something many people think about, but oddly enough I've seen a few times that people new to a lens will complain that it's supposed to be an N to N+1 zoom, but that it stays at N+1 and they don't know why.
     
  18. I haven't seen that show. Was the writer portraying the character as making a pointless or esoteric distinction? Because that seems like an extremely important distinction to me!
     
  19. I agree that it's absolutely not correct for the OP's camera provided that the switch is unlocked, with one big caveat...

    If you have image review on, and try to move the focus point while the image is still on the screen, you will end up manipulating image review rather than the focus point(left/right scrolls through images, up/down changes displayed data).

    As an immediate fix, you can tap the shutter button, which will ready the camera to shoot again and kill the image on the screen. As a longer term solution, consider turning off image review, which is something which Nikon seems to not want to make up their minds as to whether or not on or off should be the default setting. Even though after ~20 years of being around various digicams, not having automatic review after the exposure seems weird to me, I've adjusted to not having it on. The pro are that it saves battery power and leaves the camera always in "ready to shoot" mode, and to counteract the small downside of not seeing the just-shot image(sort of) immediately you just need to tap the "play" button and you can chimp to your heart's content.

    As another side note, one big benefit of the recent-ish high end bodies(D4, D5, D6, D500, D850) is the "joystick", which you can use to manipulate focus points in addition to the game pad. I've trained myself on my D500 to use it by default.

    I normally leave my control pads unlocked. Even though I'm a heavy center point user, if I inadvertently change it all that is required to center again is just a tap on the center. That's a habit from learning "modern" Nikon AF on cameras that physically blocked movement of the pad when locked, so you had to fiddle with when you needed to navigate menus or whatever else. Of course, the benefit of the physical lock is that you know by touch if it is locked.
     
    mike_halliwell likes this.
  20. This the relevant bit......

     
    Gary Naka and chulster like this.

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