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GX7, Tamron 300mm f6.3 Field Report (long)

Discussion in 'Panasonic Cameras' started by oldracer, Feb 28, 2014.

  1. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    With B&H selling the Tokina 300mm mirror lens for only $200 and an upcoming trip to Panama and Costa Rica, I ordered one to play with. Frankly, I wasn't expecting much, as the reviews say the lens is a little soft and it is not very contrasty. But at maybe 3/4 the size of my 14-140mm and so cheap, I decided it might be worth a try for the wildlife shooting. My expectations were that the experiment wouldn't work out very well and I would probably be selling the Tokina after I returned home.

    OK, now back home. Here's what I learned.

    First, the GX7 and the Tokina are a marriage made in heaven as far as handling and focusing goes. The lens has the electrical contacts, so the body knows what lens is attached and knows when I touch the focus ring. The focus peaking works like a dream. 600mm (equivalent) lenses have never been easy to focus even in film SLR days. Typically the split prism in the center of the Nikon screens would black out and focusing was done on the surrounding ground glass. It wasn't easy then and it isn't easy now, but having said that I think the GX7 peaking makes the focusing at least as good as it would have been with my various Nikon Fs.

    Like any long lens, depth of field is an issue even at a distance. With conventional glass, I could usually count on the lens stopping down and bailing me out a little bit on both focus accuracy and depth of field. Not so with a mirror of course.

    To eliminate camera motion effects, I wanted fast shutter speeds. Thus, I shot at higher ISOs than I would have with shorter lenses. As high as 3200, which I have felt is my threshold of pain with the GX7.

    Conclusions:
    • I'll probably keep the lens. The lens got me images I could not have gotten otherwise. They are not technically as nice as I would like, but they are much better than no image at all. A good one will stand printing to 8x10" and would probably impress non-photographers at even greater enlargements.
    • I never saw the extreme flare and very low contrast that reviewers have reported. I always shot with the included lens hood, though, and may not have shot anything near-directly towards the sun. I do have a photo, shot almost straight up, of a 3-toed sloth hanging in a tree silhouetted against a bright blue sky, and the contrast is just fine.
    • The lens demands patience and care. Inexact focus is punished, and the task is made more difficult when hand-holding vs shooting off a monopod (which I did sometimes) or a tripod.
    • Just finding the subject can be a challenge. It's like trying to look for things through a soda straw. My trying to locate animals or birds in a sea of green jungle was not always successful and I missed some shots as a result.
    • I didn't really have a sense that the IBIS was doing anything for me. Maybe it was, but I have many shots showing camera motion at shutter speeds under 1/500th.
    • Overdoing the ISO, which I did, gives a significant reduction in image quality. If I had one thing to do differently on the trip, it would be to shoot at lower ISOs than the 3200 I was often using. I think setting shutter priority at 1/640th and letting the auto-ISO set the exposure might be a workable strategy for most shooting.
    • It's not a replacement for the 100-300mm, which I have owned and shot in Africa. In addition to having autofocus and the ability to stop down, the zoom makes it much easier to find my subject. Start wide, then go long after the subject is located. But the 100-300 is significantly larger and more expensive.

    So here is a sample:

    This is the view from our deck in Costa Rica, shot with 35mm equivalent focal length. There is an iguana in the tree, indicated by the small red circle. He's a meter long, maybe a little more.
    P1020747-LoRes-01_w_circle.

    Here's the iguana, full frame. 1/2000th and 800 ISO. Actually it's two iguanas. I was shooting the male in the foreground when the female in the background appeared, crawling along her branch. Note that even at a distance, the depth of field is shallow enough that the female is much less sharp than the male. You can also see the odd bokeh effects of the mirror.
    P1060953-LoRes-01.

    And here's a 100% crop of the male.
    P1060953-LoRes-01_crop.

    What to conclude from all this? I'll leave that to the reader. For me, I think the lens is a keeper mostly because of its low cost and small size. I can get shots that I couldn't otherwise get and I think my technique will improve with practice. I'll use lower ISOs and use the monopod more. For a serious wildlife trip, like back to Africa, I'll pick up a 100-300mm and leave this one at home or sell it.
     
  2. AcridSaint

    AcridSaint Mu-43 Regular

    81
    Feb 25, 2014
    North Carolina
    Thanks for this writeup. I don't have GX7, yet, but I also find that the Oly IBIS often doesn't help or is marginal on 200+mm lenses. I don't even bother with 200mm or longer legacy lenses unless they have a built-in tripod support. This is probably less of a problem with the yours because it's so much smaller than long legacy zooms and primes.

    Did you only use focus peaking, or did you also try with magnification?
     
  3. Drdave944

    Drdave944 Mu-43 Top Veteran

    696
    Feb 2, 2012
    I tried focus peaking with a long lens and you get "fake" focus pealing on linear objects and leaves. You need to look for the maximum peaking. I like the manual focus magnification but you need to control it from the body not the lens.
     
  4. AcridSaint

    AcridSaint Mu-43 Regular

    81
    Feb 25, 2014
    North Carolina
    Hi Dave,

    Do you mean that the extra steps in entering magnification and choosing the focus point are an issue for you? I do feel like focus magnification is too time consuming for shooting people or time sensitive scenes, but I like the fine control for anything that I can setup.
     
  5. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    Magnification is almost impossible for me to use shooting hand-held on a lens this long. Too unstable. So it's limited to monopod or tripod use.

    That said, I experimented at home/before leaving with the magnification on and off and it didn't seem that the magnification gave me any better focus accuracy than just the peaking without magnification. I think that makes sense, because the peaking indications are the same/the peaking algorithm doesn't know whether I am looking at a magnified image or not. So on the trip I used only peaking.

    I'm not sure I would call it fake, but the colored fringing definitely seems to like some subject matter more than others. The technique I used wherever possible was to bracket the focus as a first step; get some peaking behind the subject and in front of the subject. Then I tried to focus so that some of the subject details showed the peaking. As I said, patience and care is required. There is no stop-down to bail out a sloppily focused image.
     
  6. madogvelkor

    madogvelkor Mu-43 Top Veteran

    937
    Feb 22, 2013
    Connecticut
    I have the Tokina and use it with an E-PL5 and have a similar experience. Overall I like it, the only down side is getting exact focus takes some time. I haven't tried it without IBIS on, but I didn't find shake to be as much of a problem as the shallow DOF. I've been using the VF-3 with it, but just got a VF-4 which might help with focus. No focus peaking, so I have to magnify.

    Having the electrical contacts is nice, because it allows IBIS to adjust automatically, and it records the EXIF data properly. Even though the lens is fixed at f/6.3, you don't need to worry about entering that.

    Here's a couple shots, all hand held:

    ISO 200 1/320
    <a href="http://www.flickr.com/photos/45634447@N00/12706575604/" title="Mourning Dove by aggray, on Flickr"> 12706575604_c09329e771_z. "640" height="470" alt="Mourning Dove"></a>

    ISO 200 1/500
    <a href="http://www.flickr.com/photos/45634447@N00/12572989464/" title="Bird's eye by aggray, on Flickr"> 12572989464_842f07a46a_z. "640" height="480" alt="Bird's eye"></a>

    ISO 200, 1/800
    <a href="http://www.flickr.com/photos/45634447@N00/12572652183/" title="Gull on snow by aggray, on Flickr"> 12572652183_667fab2fe8_z. "640" height="480" alt="Gull on snow"></a>

    ISO 200, 1/320
    <a href="http://www.flickr.com/photos/45634447@N00/11940348425/" title="Geese by aggray, on Flickr"> 11940348425_4c4b23df80_z. "640" height="480" alt="Geese"></a>

    ISO 200, 1/640
    <a href="http://www.flickr.com/photos/45634447@N00/11940647464/" title="Seed pod by aggray, on Flickr"> 11940647464_d550b5b124_z. "480" height="640" alt="Seed pod"></a>
     
  7. AcridSaint

    AcridSaint Mu-43 Regular

    81
    Feb 25, 2014
    North Carolina
    I've never tried magnification with focus peaking, I've always used one or the other (although focus peaking is just a cheap hack on my camera).
     
  8. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Dara
    Interesting write-up and samples. Thanks for sharing. Not sure what I think of the bokeh but for a compact 300mm lens, it looks respectable.

    I'm not aware of Tamron making any m4/3 lenses right now though - are you perhaps talking about the Tokina 300/6.3?
     
  9. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    Nice. I don't see any significant lack of contrast on your shots, either.
     
  10. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    ROFL. Of course. I always get them mixed up.
     
  11. biomed

    biomed Mu-43 Hall of Famer

    Aug 22, 2013
    Seattle area
    Mike
    With long focal lenses IBIS is less effective due to larger image displacement caused by camera movement. This requires the sensor correction movements to be larger and faster than they would be for shorter focal length lenses.
     
  12. Drdave944

    Drdave944 Mu-43 Top Veteran

    696
    Feb 2, 2012
    You have to set up the degree of mag you want with the scroll wheel in Panny but you can do the same with OLY. Then you push the proper FN button and it is preset for this. So it takes little time.On native lens you get to choose if the act of focus sing actuates the mag function. I wear glasses and am left handed so I can use all the help I can get. Tripod also helps. Also leaning camera on tree or laying on ground helps . Nice sunshine also helps. Photography is adaptive .