Some wisdom needed about lens information lust

Discussion in 'Lens Lust' started by headstand, May 18, 2007.

  1. Reading these forums to get more information about what lens i would like to purchase in the future There are still some thing unclear for me,
    I am wondering this after reading things about the nikon 50 F1.8 D, and the difference between the VR 55-200 vs VR 70-300.

    One of my big questions is what a fast lens is, why is it fast and why do we want to have faster lenses.

    Also i maybe need some info on the F value and maybe its related to the fast thing, as far as i know now it has something to do with the amount of light that goes through the lens towards the sensor (wasn't that diafragma also). I did read some where that a teleconverter improves your zoom but also multiplies with that F thing so you get less light on your sensor and that makes sense.

    Wel since i am asking al my questions now i will ask one more, would you miss the range between the 55 and 70 if you combine the D40 kit lens with the 70-300 VR

    Namaste and thanks for your reply.

    Aernout.
     
  2. Fast lens is a lens with a wide aperture. The wider the aperture, the more light that is let in and the faster the shutter speed you can set. We want this for sports where if you want to freeze action, you need high shutter speeds. Also need this for indoor work, as indoor lighting can be pretty poor for a camera to "see". Or nighttime outdoor sports. Or for any sort of shooting where the subject is moving, it's much easier to keep high shutter speed with fast glass. Last thing is, fast glass tends to have better optics than slow glass but lenses are heavier due to this as well.

    Teleconverter increases the zoom/focal length but yes, you do lose light as a result. 1 stop for 1.4x, 1.5 stops for 1.7x, and 2 stops of light for 2x teleconverter.

    Can't say if you would miss the range. I don't. It's a few steps forward if possible, or a small crop in from 55-70mm.
     
  3. Dayo

    Dayo

    May 1, 2006
    Bahrain
    NO.

    There is abosolutely no need to cover every single mm. You will hardly notice not having it.

    Actually, rather than going for say 18-55 and then 55-200 for instance, a bit of overlap is better as in 18-70 and 55-200.

    Back to your question, 18-55 & 70-300 is full coverage and the "gap" is totally irrelevant. So get the 70-300 to go with the kit if you like that lens.
     
  4. Depends on what you shoot. Fast lenses are for sports, wildlife, low light, etc. Slow lenses work great for landscapes. Buy the best you can afford and you'll soon know your preferences. But tradeoffs between cost, speed, weight, etc. will continue throughout your photo career. Seems like some of us get caught up in the equipment side of photography, and that can be fun in and of itself.

    Happy Shooting.
     
  5. Latens

    Latens

    77
    Oct 18, 2006
    The "lens speed" is an expression that refers to the widest aperture of a lens, when the diafragm is wide open. It is measured in f stops that have a logarithmic progression starting in 0.95 to 1, 1.2, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 64....
    Everyone would love to have very fast lens in all ranges of focal distances but optic design limitations determines that the fastest lens available are in the 50 mm range (there is a 50/0.95 Canon, a 50/1 Leitz and a 58/1.2 Nikon). These are mencioned as available light lens because they allow you to shoot with higher shutter speeds.
    As long as we distance from the "normal" 50 range to both side of the focal distance ranges (wide until 8 mm and tele until 2000 mm) the maximum apertures tend to be increasingly smaller.
    In the tele range the widest possible lens are widely used by sport and nature photographers who need to capture fast subjects like birds or planes or even Superman that you must shoot with speeds like 1/1000 of a second or even 1/8000 (in Superman case). This lens are very expensive because of it's size and construction (with large and special optical elements).
    If you increase the optical elements of a lens with a teleconverter (that can triple focal distance) you will also have a fall in maximum aperture.
    The complex variable focal distance aka zoom lens construction determines that aperture generally varies because of focal distance range (tipically a 18-200 lens is a slow 4.5 while 28-70 can be a faster 2.8 apertures, but usually they are all slower than equivalent fixed lens). The size of the elements and complexity of design determines that faster zooms are more expensive but also have better optical performances like lower distortion.
    Modern tecnology developed a system for enhancing lens use with low shuter speeds that is called VR. It minimizes the effects of lens shake in the pictures, allowing us to use those lenses with smaller diafragms. It has been aplied in long sport teles, macro tele and in zooms that have some range in the tele side, like 18-200 or 55-200.
    Regarding your question about the gap between 55 and 70 on the combination of 18-55 with 70-300, that depends on your photographic style. In my case I work a lot in that range and I would prefer, for instance, the 18-55 and 55-200VR combination and later a 300/4 because the worst part of 70-300 is really the longer part from 200 to 300, were quality decreases significantly.
    The possibility to have a VR lens doesn't increase the light available so lens with large aperture can freeze movement more effectively than lens with VR system and smaller aperture (for instance the 300/2.8VR and the 300/2) because VR allows a sharp background with lower speeds (i.e. 1/60 sec) but won't freeze the movements of the bird blurring the picture due to subject movement.

    Best regards,

    Paulo

    http://www.pbase.com/paulorbaptista
     
    Last edited by a moderator: May 19, 2007
  6. thank you all,

    Paulo, and others, thank you for your explanation, I just bought a D50 with a 18-55 kit, and yesterday i also bought a 50mm 1.8 because in the future i like to make pictures of yoga positions and i like to learn how it all works.

    I am not sure what i need for the rest, but i think that 55 is a bit to less zoom for me at this moment maybe i need the 18-125/135 range for most of the pictures, and i am not really a cropping guy yet, but its my first drsl so who knows what the future will bring. But i don't have much budget left for buying stuff so i need to look out for some 2nd handed stuff.

    Namaste,

    Aernout.
     
  7. Another thing, Aernout.
    Think about what is called depth of field, that is the part of the shot that will be sharp and this is how it relates to the lens:

    At equal aperture: the longer the lens, the shallower the depth of field.
    At equal lenght: the larger the aperture, the shallower the depth of field

    Shallower depth of field is useful for portraits, to isolate one's eyes (for example) or face against all the rest. You can see a lot of examples here.
    A larger depth of field is conversely useful for landscapes where you have to get sharp the whole scene in front of you.
    In the middle - even if someone could debate about this - there's macro. Macro shots, depending on the lens, the distance and the aperture you use, need a superfine lens tuning from middle to larger depth of fields, let's say from F8 to F32 depending on the situations. You have to consider that you often play on a millimeter more or less and that's why you need a large aperture range tuning.
     
  8. Another thing, more theoretical than practical. Every lens is - summarizing - a cilyndric barrel where all the lenses inside result in a virtual equivalent one. The focal lenght is exactly the distance from this virtual lens to the sensor / film plane and the aperture is just the ratio between the focal lenght and the (virtual) lens diameter. That is: a 300 F/4 means that the equivalent of a 300mm lens has a 75mm diameter. In fact F/4 is given by 300:75 = 4 and viceversa. Remember this is a VIRTUAL EQUIVALENT lens, not a REAL one.
     
  9. Thank you Dino,

    This is exactly what i'm trying to find out,. i need to translate your word into my dutch handbook, to bad they didn't give an english also with it, but when i'm trying to make pictures with the 50mm f/1.8 lens its not realy working out yet, Only if i am realy close like one foot from the object it works that out, when i farther away it won't work anny more like that so how can i shoot yogies with it from a more distance?
    (or did i buy the completely wrong lens for that... i thought this was a portrait lens)
    i don't have dreamweaver on this pc so i can't upload a picture to my website, but whats happening is that realy close the 50mm lens works better then the 18-55 to blur the background, but when i take some steps back its gone and more gets sharp.

    namaste,
    Aernout
     
  10. Ciao Aernout.
    I got what you need. You need to practise about useful depth of field to take yogis in their positions (asana).

    It's really a pity that I can't find out the site where I downloaded a dof tool time ago (which of course I haven't any longer, due to Murphy's law) I can just tell you, for now, to get a tripod, place the camera on it and try shooting around 24-35mm by following the distance you are from your subject. Set camera mode to A and lens aperture from F4 to F8 and observe what happens. You should be already able to frame the whole figure and keep it entirely in focus. You can check it if the D50 has the dof-preview button on the right side of the lens mount, where your middle right finger falls (I'm not sure it has). Clicking on it you will have an idea on what's in focus and what is not. The image in the viewfinder will darken but it's normal. Compared to what you see in the viewfinder just focusing on the subject, you will notice a much wider area which is sharp. For the moment, keep the 50 for portraits and whole figures at around 5-6 meters from you. If you want to use that lens, always on the tripod, you will need to set aperture around F5.6 - F8 - F11 to get enough dof, but you have to try by yourself.
     
  11. Of course, at equal distance, the shallower depth of field you need, the larger the aperture will be.
     
  12. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    Hi Aernout!

    Wow, that yoga position project sounds like a winner! You've stumbled in to one of the best ways to do photography. Your 18-55 is probably just the lens for it as well. You will want the wide angle part (18mm) to get those dramatic shots where a hand, or a foot, is close to the camera and large, and the rest of the person is further back, but shown entirely. You will also want to do 'normal' perspective (~35mm), where the person is shown entirely, with all the parts being the right size. And then you will want to isolate stuff, say an arm or face. This will be perfect for the 55mm focal length.

    The most important thing though, is the light. That's what photographs are made from, so don't skimp on it. A large studio with lots of directional and scattered light is best, or you can recreate that with studio lighting. Check out the Strobist forum for how to do that.
     
    Last edited by a moderator: Mar 15, 2017
  13. Latens

    Latens

    77
    Oct 18, 2006
    Dino,

    Great link. DOFmasterLE apears to be a fantastic tool, I think I'll install it in an old Palm while waiting for a WMobile version.

    Many thanks,
    Paulo
     
  14. Ciao Paulo
    I knew that but, while looking for it, I found somewhere else a program for the palmtop, but I haven't saved it since I haven't it: try looking on google for "Depth of field" and "tool" or "profondità di campo", you should get something just for that stuff.

    Ciao
     
  15. I am not sure why people have this impression that the 200-300 range of the 70-300VR is not good. These are some examples at those ranges and I am very happy with their sharpness, etc. I think a lot has to do with peoples handholding techniques.

    at 300mm
    [​IMG]

    at 270mm
    [​IMG]

    in flight
    [​IMG]


    in camera setting at +1 sharpening on the D200 and no pp sharpening in NX.

    Hope this helps
    Nancy
     
  16. Latens

    Latens

    77
    Oct 18, 2006
    Sorry Nancy,
    I wasn't refering to the VR version of 70-300 but to the 70-300G. I bought one last summer for birds and it didn't convince me, without contrast and poor resolution. Not sure if it is my fault of technique but did get rid of it and, since I am a proud owner of a 18-200VR, developed a serious LL for 300/4 and 1.4TC, both compatible with my walet, backpack space and hiking load limit.
    Your pictures are fantastic! Great lens you have! It could be an option for me if I didn't have already the 18-200.

    Best regards,

    Paulo
     
  17. Latens

    Latens

    77
    Oct 18, 2006
  18. No problem:wink: and thanks:smile:. I had never owned the older model just know this one is a winner.

    All the best
    Nancy
     
  19. Hi Dino,

    Thanks for your the link, i downloaded the program and it works on my laptop with windows 2000, so i will use it this weekend when i have more time to look into it. I need also to lean how to set my D50 so it uses the right settings.

    I will post later the results.

    Namaste,
    Aernout.
     
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