Old 50mm Nikon Lens

<p>Perspective depends only on where the camera-lens is to the subject. A shorter focal length just means one gathers more angular coverage.</p>

<p>This was shot with a 2mm lens; ie a cellphone<img src="http://i4.photobucket.com/albums/y148/ektar/video%20cellphone/pic042205_10beausmall.jpg?t=1230685842" alt="" width="500" height="363" /></p>

<p>This was shot with a 5.5mm lens; on a P&S digital<img src="http://i4.photobucket.com/albums/y148/ektar/TOOLS/P1010002BIGFOOT.jpg?t=1230686096" alt="" width="800" height="600" /></p>

<p>This was shot with a 50mm lens on a 35mm film camera<img src="http://i4.photobucket.com/albums/y148/ektar/LTM%20lenses/tripods-213.jpg?t=1230686275" alt="" width="558" height="374" /></p>

<p>This was shot with a 80mm lens; on a 6x6cm twin lens reflex<img src="http://i4.photobucket.com/albums/y148/ektar/biker/tripods-498.jpg?t=1230686375" alt="" width="510" height="544" /></p>

<p>This was shot with a 200mm ; 8 inch lens on a 5x7 camera<img src="http://i4.photobucket.com/albums/y148/ektar/old%20photos/MomMinnesota509.jpg?t=1230686487" alt="" width="636" height="438" /></p>

<p>Each shot ABOVE was with a "normal lens" for IT'S format shown;<br>

from 2mm cellphone to 200mm 5x7" camera.<br>

<br /> The 2mm and 200mm are the focal lengths.<br>

<br /> The angular coverage is roughly roughly about the same for educational purposes in all of theses shots.<br>

<br /> Its NOT the focal length matters; its the combo of focal length and sensor/film size that determines the angular coverage.<br>

<br /> A 50mm lens is a normal lens for a 35mm camera; a wideangle on a 6x6 cm camera; a mild telephoto for a cropped 1.5x dslr; a SUPER telephoto if it was on a cellphone.</p>

<p>Perspective is ONLY determined by the distance of the camera to the object; one could shoot the same subject with all five examples above and they would all have the same perspective.<br>

<br /> The confusion happens when folks move the camera when using a tele or wide angle lens; many folks wrongly assume the lens in some Harry Potter way warps the universe; and changes the perspective.</p>

<p>It's very hard to picture in my mind why shorter focal length gives a wider angle, maybe i should just know it :)<br />I just had a thought and that is because you are moving in closer to the subject with a 30mm instead of a 50mm it expands the overall frame?<br />I would have thought William that wider lenses for Portraiture would be less specific to the subject and less up close and personal, unless the surroundings were really dynamic in some way, just a thought and probably i might not be right.<br>

BTW Kelly why the censor on the girl on the motorbike ;)</p>

<p>Simon: here's a thought experiment to help with the focal length concept. Imagine that you're looking through a carboard tube (say, from a roll of paper towels). Now, imagine chopping that tube down to various lengths, and holding it up to your eye.<br /><br />A piece of the tube that's 50mm long, held up to your eye, would allow you to see a certain amount of scenery out the other end. Now, cut the tube shorter (say, 30mm), and notice that your eye can now see more of the scenery. It's a crude analogy but it works, conceptually.<br /><br />Now, imagine the same sceneario - but this time, you're having someone stand in your field of view. Let's say that in order to get that whole person, head to toe, to fit fully into your field of view (top to bottom), you'd need to stand 5 meters away from them. So, you'd see that standing person, and some amount of scenery behind them. <br /><br />Now, use your shorter tube. In order to get that SAME person to fit vertically within the now wider field of view the same way, you'd have to walk closer to him. So now you've got the same head-to-toe, view-filling look at your subject standing there... but you'll notice that you're also seeing more of the background. <br /><br />Take it to the other extreme. Imagine a very long tube (say, 600mm)... in order to see that whole person standing in the view, you'd have to get quite far away from them indeed. And you'd only see a sliver of the background scenery as a result.<br /><br />When we talk about "normal" focal length lenses on a camera, we're talking about a (theoretical) tube length that provides about the same angle of view that you get with your eye when looking around you. On a camera with an APS-C sized sensor, that "normal" focal length is around 30mm. On a full-frame traditional 35mm-sized film format, it would be 50mm or so.</p>

<p><em><strong>"I would have thought William that wider lenses for Portraiture would be less specific to the subject and less up close and personal, unless the surroundings were really dynamic in some way, just a thought and probably</strong></em><em><strong> i</strong></em><em><strong> might not be right."</strong></em><br /><br />Yes, I understand that comment. I think many photographers will use a wider lens for what some refer to as "Environmental Portraiture" - where the Portrait Subject is encapsulated usually as a smaller item in the larger context - and the camera is not very close in to the subjects.<br /><br />As Kelly already pointed out: Perspective is dependent solely upon the Camera's Viewpoint of the Subject and the Subject Distance to the Camera - once the Camera's Position and the Subject are Fixed - a wider lens just gives more coverage, a telephoto lens just narrows the coverage. This concept I think is not understood by some, but is instinctive to those who have been trained in cine work, especially.<br /><br />In simple terms, there are actually two steps: The Director of Photography / Cinematographer will firstly decide what Perspective is required for a scene, and then place the camera, for that Perspective. After that, the Focal Length will be chosen to give the "tightness" or "looseness" required. <br /><br />***<br /><br />Distortion of Verticals (because of a Wide Lens) and excessive Foreshortening (of body parts farther from the camera):<br /><br />With shot my of the woman at the table, I was very concerned / aware of how much her right arm, elbow and shoulder were going to be distorted, and foreshorten the Subject’s Head. In that regard I was careful about where she was in the frame and where the camera was, particularly its elevation. <br /><br />I was prepared to sacrifice the curvature of the right hand wall in the background, and keep the camera slightly higher, to lessen the apparent increased length of the Right Arm, and the resultant apparent diminished size of her Head.<br /><br />I am very careful in this regard with my Wedding Work (for money). I do not like working much wider than a 35mm or at most a 28mm lens on my 5D.<br /><br />But there are some who use a very wide lens and with great effect, for Wedding work.<br /><br />I think watching for distortion of the body parts is important to consider if you do work in close with a wide lens - perhaps it is easy to get that "wrong" . . . and that is why wide lenses are not really considered all that much, for close in portraiture. Certainly that is why I am very cautious, to the point of restraint with Wedding Portraiture, but far more "adventurous" with my other work.<br /><br /><br />WW<br /><br />I looked for some two dimensional diagrams of simple lenses with different Focal Lengths to explain the Focal Length / Angle of View matter - but the different lengths of “Cardboard Roll” is a really good analogy, IMO.</p>

<p>Guys i have something to tell you..................... I thought the fixed lens had to do with the aperture opening not the length of the lens, this must be one of the funniest things you have ever read and i am very embarrased. Stop laughing :) Now it all makes sense, this 50mm lens has made me think more about specific lens for the job and less about all purpose zooms. I really love knocking the background out this much, its so specific and sharp. This is just for example, but makes me so happy, im hung over. <a href="http://s89.photobucket.com/albums/k223/gorringeman/?action=view&current=newyears068.jpg" target="_blank"><img src="http://i89.photobucket.com/albums/k223/gorringeman/newyears068.jpg" border="0" alt="Photobucket" /></a></p>

<p>Well, if it makes you feel any better, Simon - as you go from 30mm to 50mm to 85mm and so on... lenses that are all at, say, f/2.8 <em>DO</em> get fatter around (and have a bigger aperture iris, along with that larger front element). Likewise, lenses that get longer (say, up to 300mm) but don't get a whole lot bigger and heavier... get SLOWER (like, f/5.6 wide open). This is why less expensive consumer/kit lenses aren't so big, heavy, and expensive. And it's why they're so mediocre in poorer light - less glass collecting light. It's also why professional quality constant-aperature zooms are so spendy... that's some complex optics.</p>

<p><strong><em>Guys i have something to tell you.....................</em></strong><br>

<br>

:) <br>

<br>

<em><strong>***</strong></em><br>

<br>

<em><strong>"I really love knocking the background out this much" . . .</strong></em><br>

<br>

But, more importantly you focused on one of my favourite beers. What a nice Photograph.<br>

<br>

WW<br>

</p>

<p > </p>

 

<p>Thats interesting stuff Matt, didn't know you could buy constant aperture lenses, i think i know where i went wrong with this, i got so pre occupied with the low light benefits of the fixed lens, i thought wider opening more light collecting ability, i did not think a 300mm lens had an opening that big... Honest :(<br>

Guinness for you William, me too, might need more than one after this fiasco lol</p>

<p> </p>

<p>No, the fiasco here is that I actually just spelled aperture with an extra "a" in it - I can't believe I did that!<br /><br />A constant aperture zoom is very useful. I shoot in aperture priority mode most of the time, and it really gets my goat when the act of changing the zoom lens's focal length causes an aperture I set at f/3.5 to suddenly be f/5.6. When you're using strobes, for example, that can really mess with you. All other optical compromises in cheaper zoom lenses aside, that particular behavior is a real show-stopper for some folks. I have variable-aperture lenses, and am accutely aware of their behavior when I happen to have them mounted. It's just something you have to keep in mind (or throw a lot more money at, if you want to maintain the convenience of using a zoom <em>and</em> the benefits of an aperture setting that stays where you put it). </p>

<p>Using a varying maximum aperture zoom lens, in Aperture Priority mode, and not being aware of the change in the Maximum Aperture when zooming (as Matt is discussing) is the cause of one of the most common errors - and failures - for many Wedding Photographers.<br>

<br>

The Wedding Forum has many commentaries on this specific topic, and it has been raised in the Sports Forum, too.<br>

<br>

The combination of Av and Varying Maximum Aperture zooms, is one of my "pet" topics.<br>

<br>

WW </p>

<p> </p>

<p>Is the Nikon 18-200mm a variable or fixed because that will be my next purchase, its my birthday tomorrow :)<br>

(no chance lol)</p>

<p>The Nikon 18-200mm f/3.5-5.6G IF-ED AF-S VR DX is a varying maximum aperture zoom.<br>

<br>

What this means is: at Focal Length 18mm (wide angle) the maximum aperture available is F3.5; but at Focal Length 200mm (telephoto) the maximum aperture available is F5.6.<br>

<br>

An educated guess as to the approximate Maximum Apertures available at various Focal Lengths:<br>

<br>

18mm = F3.5<br>

24mm = F4<br>

50mm = F5<br>

100mm = F5.6<br>

<br>

So, a real world impact might be: you are back in the bar and there is window light shining through and you take a skin tone meter reading from the beautiful woman's face and it gives you: F3.5 @ 1/40s @ ISO1600. <br>

<br>

You want a really nice WIDE shot - with her face and torso being bathed in sunlight and the rest of the room dimly lit, by comparison. Easy to hand hold 1/40s and you have F3.5 at your disposal - at 18mm, and you take the wide shot. What a cracker shot you get.<br>

<br>

But, now you want to zoom in and nail a really tight Head and Shoulders shot of her, just as she turns slightly the light is gorgeous across her face and golden hair - you zoom in to FL =120mm and WHAMMY you no longer have F3.5, but only F5.6 . . . and that means you need 1/15s shutter . . . and, you are now hand holding a Telephoto Lens.<br>

<br>

You just have to be aware of it . . . <br>

<br>

WW<br>

 

<p>Happy Birthday for tomorrow</p>

 

</p>

<p>Thanks for that heads up William, that is something i will always be aware of, tell me is there some sort of sliding scale of shutter speeds and f numbers or is it something you just learn over time?<br>

Thank for birthday wishes.<br>

Simon</p>

<p><em><strong>"tell me is there some sort of sliding scale of shutter speeds and f numbers or is it something you just learn over time?"</strong></em><br>

<br>

I do not understand the question.<br>

<br>

1. Are you referring to my guesses at the maximum apertures available with the 18 to 200 lens? - They were just guesses, from experience using similar lenses. From my experimenting with these lenses, the maximum aperture available usually gets smaller quite quickly when zooming from the wide angle and is usually around the smallest maximum aperture at the FL about one half of the total zoom value (i.e. at 100mm in this lens) - but it was a guess, based on experience, not a fact for any one particular lens.<br>

<br>

2. Are you referring to my calculation that at F5.6, the shutter speed 1/15 to take the shot of the woman at the bar? <br>

<br>

That is a mathematical calculation - ISO (sensitivity to exposure) Aperture (amount of light allowed to expose) and Shutter Speed (amount of time the light is allowed to expose) are all linked for any one, constantly lit scene.<br>

<br>

So if we took a meter reading from the Woman's face bathed in sunlight, and told us or exposure was: F3.5 @ 1/40s @ ISO1600.<br>

<br>

We do NOT have to use those exact exposure parameters - we could use: F3.5 @ 1/20s @ ISO800<br>

Or: F3.5 @ 1/10s @ ISO400<br>

Or: F4.0 @ 1/15s @ ISO1600 . . . <br>

<br>

***<br>

<br>

Modern / commonly used Shutter speeds listed in 1/3 stops: 1/10s, 1/13s, 1/15s, 1/20s, 1/25s, 1/30s, 1/40s, 1/50s, 1/60s, 1/80s, 1/100s, 1/125s . . .<br>

<br>

Modern / commonly used Apertures, listed in 1/3 stops: F1.0, F1.1, F1.2, F1.4, F1.6, F1.8, F2.0, F2.2, F2.5, F2.8, F3.2, F3.5, F4.0, F4.5, F5.0, F5.6 . . .<br>

<br>

Modern / commonly used ISO, listed in 1/3 stops: 100, 125, 160, 200, 250, 320, 400, 500, 640, 800, 1000, 1250, 1600, 2000, 2500, 3200 . . . <br>

<br>

Keeping any changes very simple, for any set of three exposure parameters for any scene, we can change TWO, the same number of stops (increments) at any one time . . .<br>

<br>

I think one key to understanding this concept, is to understand the words:<br>

<br>

<strong >ISO</strong> = the film or sensor’s sensitivity to light<br>

<strong >Aperture</strong> = amount of light allowed through the hole<br>

<strong >Shutter Speed</strong> = amount of time the light is allowed to expose the film or sensor <br>

<br>

So if we knock the shutter speed one increment faster (LESS time exposing), we need to EITHER knock the ISO to be MORE sensitive OR open the aperture one increment to let MORE light through the hole. And the opposite applies. And it can be over any number of increments, so long as the change is equal. <br>

<br>

Back to the bar and the woman:<br>

<br>

F3.5 @ 1/40s @ ISO1600 is the same as, (moving TWO elements 1/3 of a stop, each):<br>

F4.0 @ 1/30s @ ISO1600 (Aperture closes for less light // shutter exposes for more time)<br>

F3.5 @ 1/30s @ ISO1250 (Shutter exposes for more time // sensitivity is lessened)<br>

F4.0 @ 1/40s @ ISO2000 (Aperture closes for less light // sensitivity is increased) <br>

<br>

You can go up and down as you please . . .<br>

<br>

<br />If you, already knew that, sorry, no offense was meant - I was on a roll and just kept typing.</p>

<p>I hope all my numbers are correct :)<br>

<br>

WW</p>

<p > </p>

<p>William i tend to use the camera alot of the time in M mode, when i take the picture i look at my histogram and see which way i have to make adjustments, more or less in shutter speed when i use the 50mm or the kit lens.<br>

The blinker of the exposure window and the histogram seem to tell me what i have to do.<br>

I am joining a camera club this week, i am going to get some education and i am looking forward to it.</p>

<p>:) Great, have fun, regards.</p>

<p>WW</p>