"Kenko Extension Are A Little Sloppy. Does This Matter?"
Udon Thani, TH
My endeavour is to crack macro work so apart from dedicating more time to it I have purchased the Kenko DG tube set to start me off...
I have noticed that when mounting my 105mm f2.8 micro lens, (Nikkor), there is a fair amount of slopiness causing the lens to droop downwards. This is a little dissapointing as the 105mm is not very heavy?
I read that some of you use up to 500mm lenses with them !?
By holding the lens 'up' and letting it 'droop' I can't seem to see if there is any effect on focus. Do you think there will be? All else seems to work ok, focus & metering...
The tubes will be primarily used at home on focusing rails not in the field, so to speak.
For their price I can't complain too much. I just don't want to be working on some stacking only to find my lens dropping off!
#1. "RE: Kenko Extension Are A Little Sloppy. Does This Matter?" In response to Reply # 0 Mon 19-Nov-12 09:44 PM by glxman
South Australia, AU
Hi Nigel, I have been using Kenko tubes for some time now on a D700, Firstly with an AF-S 300 f4, and Ai 35mm, 50mm, 135mm,180mm, and AF-S 105 VR Like you, I have found a lot of movement, With just the 36mm tube I've been OK with the 300 but when I've used the whole lot of the tubes at once I've lost focus on the 300 but have still got the image using manual focus, With the 105, all OK, guess the weight reduction of the 105 makes a big difference
Haven't notice any IQ problems
If you are using the 105 or a collared telephoto lens, I would not worry
FWIW The 36mm tube and the AF-S 300 f4 has been a great combo and found this combo extremely useful in the field, less so now I have the 105 but when I have to "stand back a bit" the combo works great Regards, Gary
I used to have a photographic memory but never got it developed
#4. "RE: Kenko Extension Are A Little Sloppy. Does This Matter?" In response to Reply # 0
I saw the same thing a few years ago. I have a set of Nikon tubes, one of my shooting buddies has a set of Kenkos. We were pretty surprised at the "droop" - to the point that we went and tried to quantify the impact on image quality, since we *knew* it had to be there. Surprisingly, we couldn't actually find a problem, even at ultra-macro distances (105mm lens, all three tubes, so something like 2:1 or maybe a little more?) and wide open aperture.
He uses them with the 300/f4 AFS and I've borrowed them to use with a Bigma - but both of those are big lenses with their own tripod collars, so the tubes are only supporting the weight of the cameras. On the other hand, the cameras involved - mostly D2x but D3 and D700+MDB - certainly outweigh all of the 105mm Micros by quite a bit.
If the fit bothers you, and if - and only if - your intended lenses have aperture rings, you can opt for the ancient Nikon tubes. They are built considerably more robustly, and they definitely do not droop, even in slightly silly configurations. (To whit, a 500mm reflex with no tripod collar stacked onto three or four of the tubes, although the PN-11 has a collar of its own.) The problem with this is that it has no electronic pass-through, so no AFS, no VR, no metering unless your camera supports metering with AI lenses, and these days the Nikon tubes are getting slightly ridiculous in price.
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!
#5. "RE: Kenko Extension Are A Little Sloppy. Does This Matter?" In response to Reply # 4
Udon Thani, TH
Thank you for your input. I have now done some test shots and I too cannot see any appreciatable difference between the lens drooped or supported. I thought I might? I also tried shining a very bright torch on top of the tubes to see if they allowed light leakage when drooped and again; no...
On a bench with a proper set-up I measured the actual droop to be 3.5mm from supported to un-supported. Whilst it looks quite a bit I guess the change in the 'planes' between the lens and sensor is incredibly small?
So to summarise so far they appear to work fine despite this droop.
I looked for Nikon tubes before deciding on the Kenko's. All my lenses are G lenses so the manual tubes were ruled out early on. I also looked into the Nikon bellows with the link cable set-up to maintain camera/lens communication but cost was super high. So, as I am only starting off with macro I decided to go with the Kenko's as they had pretty good reviews in use...
#7. "RE: Kenko Extension Are A Little Sloppy. Does This Matter?" In response to Reply # 0
I've owned 2 sets of Kenko tubes. Two of the tubes in the first set met with an untimely demise, so I got a second set. Interestingly enough the first set was a bit sloppy and I could only mount one on my 300f/4 without losing metering (fEE error). All 3 would mount on the 105 with no problem. I never could detect any degradation in IQ in either case.
The second set mounts more tightly and I can mount the 2 larger tubes on my 300f/4 with no problem, I haven't tried all 3. My use is for work in the field and I'm carrying around the 300 mounted with tubes on a tripod. So far no problems.
#8. "RE: Kenko Extension Are A Little Sloppy. Does This Matter?" In response to Reply # 7
Udon Thani, TH
Thank you Nikonians for your repsonses...
Looking into this subject has unveiled a range of valued comments from you all. I found out today by looking at more tubes in a store that they posessed the same/similar amount of sloppiness in the mounts as my set. I also found out that a majority of manufacturers use 'cantilevered' tabs to provide a secure locking action between tubes/lenses... Kenko included. This is where I think the Kenko might fall down somewhat? These cantilevered tabs act like springs and the 'mainstraem' manufacturers seem to have much stiffer spring actions which make the jointing of such items feel much tighter. The Kenko cantilevered tabs are quite soft in comparison, (in fact I can quite easily compress them with my finger nail). This softness appears to allow some play between the tubes, especially if the lens is larger/heavier.
#9. "RE: Kenko Extension Are A Little Sloppy. Does This Matter?" In response to Reply # 8
Hi Nigel, have had exactly the same play with my set with the 105VR attached.
When I have used 2 or three tubes with the rig on the focus rail I found I could place a support (folded paper) between the lens barrel and rail top face. This simply reduced the loading and strain making me happier.
#11. "RE: Kenko Extension Are A Little Sloppy. Does This Matter?" In response to Reply # 10
The play appears to come from the 'interference fit' between faces of the male and female halves of the bayonet flanges.
These will be manufactured between certain tollerances and of course different manufacturers 'could' use different tollerances. Types of material, their differing expansions rates caused by temperature and frictional properties may also have some affect.
I suspect the designers and engineers err on the safe side of loose rather than tight. The reason being that if the pinch between bayonet faces was made too tight unwanted strain would be placed on the other lens/tube components inbetween the bayonets during mounting and dismounting.
This would be more relavant today with the increased use of plastics inbetween.
#12. "RE: Kenko Extension Are A Little Sloppy. Does This Matter?" In response to Reply # 11 Sat 24-Nov-12 08:08 PM by EnEs63
Udon Thani, TH
AartPapaya, (interesting username?...Is this anything to do with Papaya from Thailand?).
Stage coach is exactly right....
The tubes I have discussed here are the DG (Auto) tubes from Kenko. Not wanting to be too critical they are not as 'well' made as perhaps mainstream manufacturers products were, especially from years ago where quality seemed better than modern products?? They are, after all, mainly plastic bodied and tolerances, as Stagecoach mentions, plays a big part with plastic.
The reasons I chose Kenko was; Nikon, I don't think make tubes anymore. (They used to be all metal !). The second hand market does offer some but they are expensive. Even if I did buy the Nikon ones they were completely manual, (I.E. no autofocus or metering connectivity).
Kenko's did have a good 'write-up', probably the best of the modern-day third-party market so I took the plunge. Yes, I was concerned of the sloppiness but having looked into and tried them they work perfectly ok. I will use a support the same as Stagecoach as well, for peace-of-mind as stress on any joint cant do it any good...
For the price one really cant go wrong... go for it...
BTW I will be posting my very first image of a stacked macro shot using the tubes on this site this evening.... take a look at "My First Stacked Spider"...