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Thread: Learning about lenses!

  1. #1
    geraldlieteau's Avatar
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    Learning about lenses!

    Opteka 650-1300mm High Definition Telephoto Zoom Lens for Nikon
    Opteka 650-2600mm High Definition Telephoto Zoom Lens for Nikon
    ************************
    Im looking at these lens on eBay because I want to take pictures of the moon and other things down here in the swamps. I have a Nikon D3100. What is the story behind these lenses if there is any? And what makes a cheap lens cheap? Thanks for the advice and answers.

  2. #2
    Shadowman's Avatar
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    Re: Learning about lenses!

    Fewer lense elements, one aperture, small angle of view, manual focus. You should be able to get some decent moon shots, also lens is super as a video lens. I'd purchase it new if i were you, it is a very cumbersome lens and if not handled well could have been the victim of some major bumps and bruises. I've read where it can be shot handheld but why would you, this lens is 18" at 650mm.

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    Moderator Dave Humphries's Avatar
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    Re: Learning about lenses!

    Hi Gerald,

    Have you checked out the user reviews on Amazon (UK)?
    5 star 0
    4 star 0
    3 star 1
    2 star 3
    1 star 0

    The manufacturers spec says all the right things, but the feedback tells another story, mainly centred on usability issues.

    HTH,

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    evan47's Avatar
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    Re: Learning about lenses!

    my advice is to leave well alone. at the price they are asking if they were any good they would be popular.

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    Moderator Dave Humphries's Avatar
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    Re: Learning about lenses!

    Being a pedantic cynic with a sense of humour, I wonder if they justify the use of the words "High Definition" in the description because that is the resolution it matches - "HD" being (at best): 1920 x 1080 = 2MP, leading to disappointment on anything greater

    That said, if you Google "Opteka 650-2600mm" and see some of the images, there is the odd good one (if usually vastly downsized).

    I use a 1000mm FFE Nikon P510 and keeping that steady handheld is tricky enough with IS.

    At 2600mm (x c/f?) and no IS, I can see why one or two tripods will be necessary just to keep the subject steady in shot and not get camera shake or droop during an exposure.
    Last edited by Dave Humphries; 30th March 2013 at 07:05 PM.

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    Re: Learning about lenses!

    Yes hand holding long lenses can be a problem ... why I like my camera set to give me a one second review .. enough to see if the subject is actually in frame despite my wanderings

    On the other hand with OIS 2000mm reach is quite reasonable with fairly slow moving subjects as I found when I made a rare visit to the local beach and shot the surfers from the esplanade. Camera and lens gave me 950mm and around a quarter crop provided the rest for web use ... plus editing
    This guy was closer to me so all of my x12 zoomed FZ30 8Mp frame with the Raynox 2020 back in 2006.
    Learning about lenses!
    And a bit of fun from the same day "Going...Going...Gone"
    Learning about lenses!

    I suspect without knowing the lenses the answer to if you will be happy with one of them is what standard of result you expect and how competant you are with editing

    Exposure 80 ISO 1/1000 f/3.7 effective about f/4.5 with Raynox
    Last edited by jcuknz; 31st March 2013 at 01:15 AM.

  7. #7

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    Re: Learning about lenses!

    As to the swamp photos have you thought about a hide and waiting for the creatures to come to you ... or would the gators get you first.

    Second thought if you price a 2/h FZ50 along with the Raynox 2025 [ it has provision for a lenshood which is needed ] about $500<$600, you could get what you are after for maybe the same price as the Optekas ?
    Plus I see the dealer has it wrong as it is not a teleconverter but either a tele-adaptor or else a telephoto lens or a long focal length lens. I suspect it is a telephoto fixing directly to the camera..
    this is my rig with my drain-pipe connector for a lenshood. and improvements for hand holding ... not got around to making them as yet
    Learning about lenses!
    You may see the collar I made out of 3" thickwall aluminium tube which is tapped 1/4" to mount on a tripod at roughly the point of balance ... something you would need for the Opteka's too probably, or a lens collar if they don't come with a tripod mounting collar etc. If making/getting a hand support as drawn you would also need a remote release to trigger the camera while holding the grip ... left hand focus's the lens right hand holds rig and works release .... live view provides the confirmation of what you have taken without moving camera from eye.
    Last edited by jcuknz; 31st March 2013 at 01:48 AM.

  8. #8
    geraldlieteau's Avatar
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    Re: Learning about lenses!

    Thanks guys for all the info. I have a much better understanding of lenses. I think I may get one of the lenses to see how it works. Sometimes gotta spend the money to fill a simple need.

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    Black Pearl's Avatar
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    Re: Learning about lenses!

    We haven't always had IS but photographers managed to take pictures without it.

    One other thing to consider is while you can certainly get a tripod/firing solution that will limit the amount of shake at the magnification we're talking about using a 2600mm lens the moon will be visibly moving within the viewfinder and you're range of shutter speeds will be limited.

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    Moderator GrumpyDiver's Avatar
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    Re: Learning about lenses!

    Quote Originally Posted by geraldlieteau View Post
    And what makes a cheap lens cheap?
    There are four major factors that affect what if costs to make a lens:

    1. Material costs this is effectively the cost of the raw materials that go into the lens. Materials that are chosen for any product for their properties, such as strength, temperature stability, impact resistance, etc. Optical elements are chosen because of the index of refraction that they offer (amount that they bend light). As a general rule of thumb, the more demanding the performance characteristics, the more expensive the raw materials will be.

    2. Production costs lenses have to be ground, metal parts have to be machined and plastic parts have to be moulded. Finally all of these parts have to be assembled and packaged.

    The more parts there are, the higher the production / assembly costs. Higher precision operations will be more labour intensive than lower tolerance ones. If production volumes are high, automation can reduce production costs, but the equipment and tooling will be more expensive.

    3. Design and start up (tooling) costs - it takes knowledgeable and skilled people to design the lens (mechanically and optically). Likewise and speciality tools, for instance moulds for plastic parts have to be designed and built. Using aluminum rather than steel in moulds will significantly reduce mould costs, but aluminum moulds will wear out faster.

    4. Warehousing , shipping, taxes and duties the raw materials and finished goods have to be stored, so warehouse space costs money. Transport from the factory to the importer and retailer add to the costs. Governments collect import duties and taxes along the way.

    All of these costs have to be absorbed and go into the cost of every lens you buy.
    The manufacturer will want to make money on the lens, so there will be a mark-up on the various costs.

    These products are often handled by an importer, so they will take their cut, and finally the retailer will charge a markup as well, whether they are a bricks and mortar store, or an on-line operation.
    So, what makes a cheap lens cheap? Minimizing the costs; this generally means reducing the quality all along the supply chain.

    I personally suspect you will find this lens to be very difficult to use. I can generally handhold a 400 or 500mm lens, but you will find that these long focal lengths will be challenging to use. The lens is manual focus, and I dare say this will be very challenging on your D3100; the viewfinder, which was never designed for anything other than autofocus. You will find shooting a lens with a maximum aperture between f/8 and f/16 to be challenging.

    I hope you have a good, heavy duty tripod; you will need it to shoot with this monster of a lens.

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