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Activity : All Comments

  • Commented on 'UV Filters'

    The image quality problem with filters is not so much a loss of sharpness, but flare and ghosting (as LenShepard has said) which can be very noticeable indeed - even with the most expensive multicoated filters.

    Sure there are sharpness issues too, especially with longer lenses (polarising filters are often quite poor here) and you can also get some strange bokeh problems with distracting patterns appearing in out of focus areas (longer lenses again).

    But the biggest problem by far is caused when shooting bright lights against a dark background. Street lights, sunsets, car headlights, neon signs etc.

    With subjects like these you get flare around the light source itself and, if you look very carefully indeed, a reduction in contrast over the whole image in extreme cases. Worst of all is the ghosting that LenShepard mentioned, which is a digital effect caused when the image bounces off the mirror-like surface of the sensor, and then back again off the rear of the filter, creating a duplicate image.

    Anyone that says filters don't cause any noticeable degradation has not tried shooting street lights at night! I have a protection filter, and use it when I need to - usually the only time is to protect from sea spray. Otherwise it stays very firmly in the bottom of my bag.
    • 30 Aug 2010 3:09AM
  • Commented on 'Off camera flash triggers'

    One way of retaining remote E-TTL when the optical triggering is unreliable, it to use a 10m extension cable - about 40 on ebay. This usually allows you to position the master unit close enough to the remote slaves for the optical system to work okay. Obviously, you have a cable hanging about...

    To do it wirelessly with E-TTL, it's either Radio Poppers which you can't get over here, or Pocket Wizards that have yet to gain full user confidence. It's a brilliant system when it works though - does things that Canon can't (Hypersync etc).

    Otherwise, it's full manual and the Yongnuo RF-602 is the one to get. Reliable, good range, and still only 30 a set. I've got five Wink
    • 12 Jul 2010 4:28AM
  • Commented on 'soft box vs umbrella softbox'

    Umbrella boxes work fine from a little distance, but you can't use them very close because the flash head and shaft get in the way. Plus you get a reflection of the head in the catchlights. Very quick to put up though, and cheap Smile
    • 12 Jul 2010 4:12AM
  • Commented on 'Has anyone tried using this...........'

    Welding glass works, if not as well as the real thing. You can get them for a couple of quid off ebay, or 3.50 from Machine Mart. They come in various strengths numbered something like 9-14. Mine is marked 11 and is about 14.5 stops. They are all very green so you must do a custom white balance, or correct in post processing.

    They are a faff to use though. Most people get something like a Cokin adapter and glue it to that. Blu-Tack works okay. Make sure it is sealed all the way round or you'll get light leaks. Seal the edges too. By the same token, cover the viewfinder during exposure as light gets in there and creeps around the mirror causing fogging and streaking.

    The Lee Big Stopper is good for square filter users. It is almost neutral (a smidge blue) and has a neat foam gasket that seals it from light leaks against the filter holder.

    I'm not over-impressed by the B+W ten stops jobbie, as it's a bit orange and not coated, which it should be for the price (neither is the Lee, come to that).

    I think the best ND filter is the Light Craft Workshops ND500 which is nine stops. It is also very slightly blue like the Lee, but is multi-coated and much cheaper. 77mm screw fit only, 58 from Premier Ink here

    Hoya make a nine-ish stops X400 but it's pricey and special order only.
    • 3 Jul 2010 10:37PM
  • Commented on '1D Mk iv - 5D Mk ii'

    You haven't said what your main shooting priority is, but as a general all-rounder you're probably right in going for the 5D2. It has probably the best sensor available, both for resolution and high ISO, and it's not as slow as you might think from the reviews. It rattles along at almost 4fps and the AF is better than it's cracked up to be - I was surprised at how good it was for motor sport on servo AF. For long lens photography it is also better than you might think, because if you crop the images to the equivalent of an APS-C 1.6x format you are still left with an 8mp image, which is similar to a 40D for example.

    But for long lens action and wildlife, the 1D4 is peerless. It is lightning fast at everything, plus it has the 'reach' advantage of the 1.3x crop sensor. One drawback is that it won't take EF-S lenses so is a bit compromised on the wide-angle end. You can do a DIY mod on the EF-S 10-22 to partly get around this (basically remove the rubber gasket so that the rear of the lens clears the mirror - google it).
    • 3 Jul 2010 10:14PM
  • Commented on 'New Camera/Lens'

    Canon 100-400L is probably the favorite choice for aviation, as stated above. Since you can't change either your shooting position, or the distance of the aircraft, a zoom is obviously very useful.

    Optically it is not far behind the 400L, plus it has IS.
    • 3 Jul 2010 9:58PM
  • Commented on 'Novice in search of help!'

    Close-up lenses are a very cheap and easy way of getting into macro. They come in various strengths, like +1, +2, +3 diopters and these will get you usefully closer. The best quality ones are coated, eg Hoya.

    But if you want macro, the Raynox DCR-250 adapter is a much stronger supplementary lens for close-ups. It is +8 diopters and will usually get you down to 1:1 with most lenses. It will work very well on your 55-200. Unlike simple supplementary lenses it is a fully coated triplet design. It costs about 40 and will fit any lens up to 67mm filter thread There is also a less strong DCR-150 version which is maybe better if you don't want to go too close, for flowers and butterflies and stuff.

    While supplementary lenses are not such high quality as a pukka macro lens, you may never notice it unless you shoot critical flat subjects like stamps or coins. The reason for this is because with macro the depth of field is very shallow so three quarters of the frame is out of focus anyway and a little bit of softness at the edges doesn't matter. Secondly, also because depth of field is shallow, you tend to have to use a quite high f/number and this reduces lens aberrations. So at f/8, f/11 etc, the Raynox will probably be pretty sharp!

    Here are a few sample images I prepared earlier Wink
    • 3 Jul 2010 9:50PM
  • Commented on 'UV or Skylight filter (1A, 1B etc.)'

    A skylight filter is a very slightly pink version of a UV - put them both side by side on a sheet of white paper to see. They are both designed to combat the slight tendency to blueness that some films are prone to, at high altitude, seaside etc.

    Neither has any place in digital photography, as all sensors have both UV and IR filters over them. They are only of use for physical protection. Dealers like them because there is a high profit margin in accessories and, basically, they spin you a yarn.

    Using filters for no reason can and does cause image degradation. The problem is not sharpness as commonly thought, but flare and ghosting. Flare, which causes a slight overall reduction in contrast, is created by having two extra glass surfaces in the optical path, although coated and multi-coated filters are much better for this.

    Ghosting is rather worse, and is a new problem for digital. It is most noticeable when you have bright highlights against a darker background, like a sunset, or street lights at night. What happens is that light bounces off the mirror-like surface of the sensor, and back again off the rear of the filter.

    Basically, unless you have a real need for physical protection (eg sea spay, mud on a rally etc) then don't fit a UV/Skylight filter. Use a lens hood for protection, and that will actually enhance image quality in some situations.
    • 3 Jul 2010 9:22PM
  • Commented on 'Advice please , canon 70-200 f/2.8Lusm or 70-200 f/4 is usm'

    I chose the f/4 IS version. It is half the weight of the f/2.8 versions, which are really heavy lenses - about the same as the very substantial 100-400L. Get to try before you buy Wink

    F/2.8 is obvioulsy nice to have, but unless you use it on a fairly regular basis you are carrying it about for no benefit. Also, looking at the two lenses you have selected, you will miss out on the finest incarnation of Canon's four-stops IS system, which is arguably more useful than an extra stop of aperture. Plus the f/4 lens is fractionally sharper, it has weather sealing and a cirular diaphragm for nicer out-of-focus background effects.
    • 3 Jul 2010 9:07PM