How to understand lens capabilities and know which is best for purpose.

Discussion in 'Photography Equipment & Products' started by PJcam, Jan 18, 2018.

  1. PJcam

    PJcam No longer a newbie, moving up!

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    I am sure to some this is a silly question, but I always believe all questions are easy if you know the answer and no question should be called silly, the question is submitted to get a better understanding.

    As you can see from my Signature, I am very new to photography with no real knowledge having only really used a mobile phone or press and shoot basic camera over the last 25 years or so.

    I think I got off to a good start with my camera and lens, thanks to @TCampbell, but although I understand I have a wide angle lens, a standard range lens and a telephoto lens, I have to admit I am not sure how I would I chosen them had I not had a package deal.

    That said let me look ahead to a super telephoto lens, can't afford yet and need to get to know the camera first but, rather than wait until I can afford I ask this question now, so that I get a better understanding of lens options.

    Lets say I am looking to shoot wildlife, at distance, how do I know which lens is best, or better put, which is the best for the purpose subject to my budget. Budget aside for the minute, I say to myself, whether I can afford a budget lens, a mid cost range or a top range lens (last one is definitely out), in each category I am going to have options, what is the capabilities or possibilities of a lens, how do I work this out based on the f/ and the mm, one lens against another.

    I am sure the question has been asked before, I am not asking which is the best based on cost but on lens information, I just want to understand it better.

    Everything I have so far is Canon, I have a T6 Rebel 1300D EF-S

    Thanks in advance.


     
  2. SCraig

    SCraig Been spending a lot of time on here!

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    Start Here. Specifically the section on "Camera Lenses"
     
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  3. vintagesnaps

    vintagesnaps Been spending a lot of time on here!

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    I'd rather get a lens that's sharper and better quality and buy it used if need be, or save up for a new one, than to get something lesser quality and not that sharp. Seems like usually a sharp lens is at least an f2.8; kit lenses seem to often have very little aperture range and may be only something like f3.5 to 5.6. I have a couple of vintage lenses that are maybe f4 I think (I'd have to go look!) and they were cheap, but more limiting to use.

    I usually use them out on a nice sunny day because they need plenty of light with the smaller aperture range. If they hadn't been cheap and anything better (even being vintage) costs way more, I probably wouldn't have bought them. Depends I guess on how you would use them, these are for film rangefinders that I don't particularly depend on.
     
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  4. jcdeboever

    jcdeboever TPF Supporters Supporting Member

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    Just look in the wildlife threads on here for your answer. From experience, I don't trust Sigma at all, it's a roll of the dice on accurate focus. I am not familiar with Canon Digital but I think someone on here is posting nice images using the newer Tamron 150-600 g2. TAMRON | SP 150-600mm F/5-6.3 Di VC USD G2.

    Of course, any L glass will be fabulous but expensive.
     
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  5. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    First up one of the most important things to understand is that no lens has a specific "use".

    Taking your example of wildlife you can shoot wildlife with every single lens that you own. From the 10mm to the 300mm. However if you take your lenses out yourself and put them to your eye you'll find that the 10mm gives a very wide view of the scene, things in the distance will be very small to the frame. As a result if your wildlife is far off you won't get a close up view of them, instead you'll get a landscape style photo of them.
    Of course if you've got a robin hopping up close you might well find it can fill the frame very nicely!

    So even from that simple test you can see that a longer focal length will be more suitable for wildlife photography in general, where your objective is a body/portrait or at least closer shot. However if you've got a huge herd of deer before you you might well want that wide angle yet again.


    And there we get to the key part, your intentions and situation.
    Your creative intention for the photo starts to define what lens might suit best; meanwhile the situation (eg how close you can get for wildlife) will further start to dictate what lens would be suitable to get closest to your intended photograph.



    Now of course, there are conventions and standard use. For example of your three lenses the 70-300mm would be the one most would suggest is the wildlife suitable lens whilst the 10-18mm the most suitable landscape; whilst your 18-55mm would be a portrait type lens, with wide angle landscape as well.

    These conventions are the most useful and generally "workhorse" choices for people based upon most common results. However they are not the only choices and you should always be willing to experiment and play around and see what works for you. You might well find that your own creative desires are not "standard" and that you might well make choices others don't.


    Now on to f number of the lens. The f number - ergo maximum aperture (smallest f number = biggest aperture = smallest depth of field and most light gathering) of the lens is just that. It's the widest the aperture blades can be set too, ergo when the lens is letting in the most light to the sensor.
    This influences your light gathering for the camera as well as the depth of fields possible. A wider aperture (smaller f number) means that you can get a thinner depth of field and a greater amount of blurring of the background.

    Now if you've been learning about exposure control (eg by books like Understanding Exposure by Bryan Peterson )then you'll appreciate that a wider aperture means that you've got more latitude to shoot in lower lighting before just raising the ISO or lowering the shutter speed.
    In very general terms as well, the higher quality lenses (better optics) tend to go hand in hand with wider maximum apertures - esp as the wider apertures mean bigger lens glass and thus more inflated cost.



    For wildlife your shutter speeds often have to be fast to account for the subject moving; in addition if you are hand holding a long focal length lens you'll need a faster shutter speed to achieve a clear sharp shot. So speeds of at least 1/500se or 1/640sec are going to be your minimum shutter speeds (roughly). This will often mean that you are raising your ISO up to 400, 800 or even higher. So if you've got an f2.8 lens instead of f5.6 that's a few stops more of light gathering - that means faster shutter speeds at lower ISOs.
     
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  6. PJcam

    PJcam No longer a newbie, moving up!

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    Hi all

    I am going to come back to each reply in turn, many good points are raised here, and good links provided which I will spend time going through. It won't be today. Meanwhile thank you.

    If I was to pick one comments at this stage it is 'You might well find that your own creative desires are not "standard" and that you might well make choices others don't'. That sort of hit the nail on the head. It is not that my desires or choices are different, more that my lack of mobility, using a power wheelchair, restricts me from getting places others can get to. Hence the serious consideration for when I am ready to afford/purchase an ultra zoom lens to reach that next level. Reaching being the key word here. So I say to myself an f/2 would be good due to the extra light it allows into the lens and is faster as a result, but an f4.5 though may not be as good but may be more affordable for image reach with a zoom lens.

    I guess the bit I find frustrating, due to lack of sufficient knowledge is, which lens is best, for my situation, an f/2 200mm or a f/4.5 400mm. Light vs zoom capability. Which would give me a good full frame shot, both, but at what distance one compared to the other. I accept many smaller birds, robins etc can be very close and the lenses I have would be fine, but when I go to reed beds and lakes, nature reserves, where animals or birds can be at a distance, many have to be photographed at distance to get the shots without spooking them.

    I am sure others have thought it also, especially beginners like myself, I can find the lens data but do not know how to equate that into distance. Light being a separate decision although an important one, early morning, disk, in trees etc.

    From my thinking based on my little knowledge, the f/4.5 400mm seems the best but at the cost of light. The f/2 200mm being much better in many ways but the zoom would maybe not give the distance I might need.

    Those things in mind, there has to be many on the forum who have taken animal and bird shots, there is, great images have been shared and the camera settings also. May be some of you guys could say, I took this with an f/4.5 400mm at this distance and this with a f/2 at 200mm. If that is possible and the distances are realistic it would help me I am sure.

    Or maybe there is a way of calculating this? I am open to all suggestions and help.

    Thank you in advance, as stated above I will come back to your messages and links tomorrow.
    (I hope what I have written makes sense)
     
  7. BrentC

    BrentC Been spending a lot of time on here!

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    Because you want to shoot birds and you have mobility issues the longest lens you can get would be best. 400mm f4, f5.6 is fine. F2.8 or lower will be huge, heavy, incredibly expensive lenses and for the most part you are going to be shooting wildlife in decent light. Or you can go with something like the Tamron 100-500 zoom. But they are still going to be big lenses. Maybe a 300mm f4.
     
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  8. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    Based on your situation I would say that you will fit into the most typical block for what you'll need for wildlife - which means the rule is
    "The longest focal length you can justifiably afford"

    For places like reserves with a hide a 400mm would be the shortest focal length that I'd go with. Sure sometimes stuff will come closer, but many and most times it won't. And if you want those closer shots you will want that focal length. Sure you lose some aperture, but don't forget you've got your ISO and modern cameras can raise that to high values without a huge impact on image quality.

    The Canon 400mm f5.6 is a very popular lens - its not only giving you a long reach, but it also is light enough to make it easier to hand hold.
    There are also a range of 3rd party options such as the 150-600mm lenses. These offer decent image quality with a greater range of focal lengths. Canon also has the impressive 100-400mm MII (the original version of this lens is decent, but the newer is a significant improvement). Of course once you are past those lenses the next ones up are bigger, heavier and much more expensive - but the mid-range are very good and widely used.
     
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  9. PJcam

    PJcam No longer a newbie, moving up!

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    You have take a lot of wildlife shots BrentC, what sort of distance would I get of a swan or large duck filing a good percentage of the frame from an ultra telephoto lens like the Canon EF 100-400 MM F/4.5-5.6 L IS USM Lens. Do you have s similar one? I appreciate at times distance is hard to quantify.

    I have tested the three lens I have on a tripod, each at min and max settings to get a feel of what is possible from each so I have a good idea, I think I have reasonable coverage from the three lenses, it is just the extra distance for wildlife, and when I am ready I want to make the right decision, it is the most costly lens.
     
  10. PJcam

    PJcam No longer a newbie, moving up!

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    Thanks SCraig, the page is very helpful. But I still have questions as you will see below. I have saved the website for future reference.
     
  11. PJcam

    PJcam No longer a newbie, moving up!

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    Hello again Sharon, (the other) Sharon ;o)

    Thank you for your comments, sharper, brighter and quality are all important, but I have three lenses that get me, a to b, b to c, and d to e, distance.

    I know I am limited to smooth paths, or smooth tracks, unless my car will get me a little further. I cannot go across fields or any such terrain, so distance with a lens is an important consideration for me, more than most people who can trek the countryside. For this reason I am being very careful as it is the most costly lens I will have, but I would really like to film wildlife, not just the garden birds, I could do them with the lens I have, but those in nature reserves, on beaches, etc. I cannot get there but a lens may be able to, it just depends how far the lens will zoom to give a deer or a bird for example a close to full frame shot. For me it is still an unknown factor but as said distance a lens will zoom is very important for me.

    Thanks again for your comments, I appreciate all comments people take their time to add.
     
  12. PJcam

    PJcam No longer a newbie, moving up!

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    Thanks jcdeboever, I have looked at wildlife images members have added and they make me more determined to have a go myself. But my question is how far will a zoom lens zoom in metres, for me to judge what is suitable for me. Like the example lens quoted earlier.

    Thank you for your comments.
     

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