Ash nazg durbatuluk (or not).

[Andrew Garrard]

<p>Hi all.<br />

<br />

I have an 80-200mm f/2.8 AF - first version of the one-ring designs, not AF-D as far as I can tell. I think this

is my first AF lens that's not AF-D. The autofocus is fine (if expectedly slow).<br />

<br />

I'm slightly confused: used on my D700, the metering seems to be wildly wrong unless I manually set some data in

the "non-CPU lens data" menu - and obviously I can only do that for one focal length at a time. If this was a

non-autofocus lens, I might expect that behaviour, but I had thought "AF" was sufficient for the camera to know

what's going on (and just switch from 3D matrix meter to "normal" matrix meter - although the other metering

modes don't seem to be much better).<br />

<br />

I have auto-ISO enabled; it appears that the camera is massively over-exposing when the lens is supposedly

stopped down. Setting the aperture via the aperture ring or from the camera makes no difference. The aperture

<i>does</i> change - I can see this in images; the aperture changes when the lever is manually manipulated, and

other lenses are fine on my camera. It's as though the lens is AI but not AI-S and the camera doesn't know.<br />

<br />

I may need to do more experimentation to work out what's going on, but I was wondering whether this is normal

behaviour for one of those lenses. I've not tried it on my F5 yet. I've just leant the lens (with an instruction

to use it only at 200mm unless she want's to check the histogram and use exposure compensation a lot) and camera

to a friend who's (co-)shooting a wedding tomorrow so I can't do immediate tests, but it's be nice to know

whether I'm looking at an unwell lens or whether working around the issue is expected.<br />

<br />

Fortunately, the reason I went with a mark-1 80-200 is that it was relatively cheap... (I'm just starting a new

job. Maybe when I've finished paying off my 200 f/2 I should look at a 70-200 VR II...)<br />

<br />

Extra information: if it matters, the 80-200's aperture lock is broken. Otherwise the lens appears to be in

decent condition, aside from a few cosmetic scratches on the exterior.<br />

<br />

Any thoughts would be welcome. I'm puzzled.</p>

[CoryAmmerman]

<p>I think I vaguely remember reading somewhere that distance info is necessary for matrix metering, but don't quote me on that. I'm sure someone will be on here soon enough that knows for sure. Have you tried center-weighted metering to see if you get more accurate results? I'm pretty sure distance info isn't necessary for center-weighted, and this seems easier than trying to manually enter non-cpu data for a zoom.</p>

<p>Edit to add- after a search I read that you should still get matrix metering with a non-d lens, but not 3D matrix metering.</p>

[ilkka_nissila]

<p><em>distance info is necessary for matrix metering,</em></p>

<p>Of course it is not. Matrix metering is something that Nikon invented in early 80s. Distance info makes a very minor effect on exposure. It sounds like your lens is in need of service.</p>

<p><em>with an instruction to use it only at 200mm unless she want's to check the histogram and use exposure compensation a lot) and camera to a friend who's (co-)shooting a wedding tomorrow</em></p>

<p>You <em>what</em>? You lent a broken lens to someone shooting a <em>wedding</em>?</p>

[Michael R Freeman]

<blockquote>

<p><em>"I think I vaguely remember reading somewhere that distance info is necessary for matrix metering..."</em></p>

 

</blockquote>

<p>It is not. :)<br>

-</p>

 

<blockquote>

<p>"<em>It's as though the lens is AI but not AI-S and the camera doesn't know."</em></p>

</blockquote>

<p>Doesn't matter. The difference between Ai and AiS has no impact whatsoever on metering or exposure. In fact, the D700 has no means to detect and distinguish an AiS lens from an Ai lens (this function is limited to a select few film bodies)<br>

-</p>

 

<blockquote>

<p>"<em>Extra information: if it matters, the 80-200's aperture lock is broken."</em></p>

</blockquote>

<p>Again, doesn't matter. This is a simple mechanical interlock that has no influence on exposure, metering or any other camera function. It's simply a lock to keep a user from accidentally moving the lens aperture ring from minimum aperture without noticing.</p>

<p>Does the lens expose correctly at f/2.8?</p>

<p>If it exposes correctly at f/2.8 but overexposes at other apertures, then your lens aperture may be sluggish even if the blades do close when manually manipulated. A sure sign of sluggish aperture blades is that the overexposure will get progressively worse the further you stop down from wide open. Or a sequence shot at the same aperture but with high speed frame advance will show progressively worse overexposure (the aperture stopdown can't "keep up" with the frame rate).</p>

[Andrew Garrard]

<p>Thanks, guys. The metering seemed to be playing up even in spot metering mode - centre weighted was certainly iffy, but I had limited time to experiment. I'd understand if it was a variable aperture zoom, but since it's a fixed f/2.8 I can't really understand how it can be managing to misbehave. Ilkka - as you say, I may end up taking it to Nikon UK and asking whether they can fix it for a suitably small fee. I did see a little more bloom around contrasty edges than I might have expected - so it may be a 350 quid paperweight in disguise. It's taken me a while to give it a trial run, so I may have to take the hit if the retailed isn't generous. If Nikon can't fix it, I'll just save up for a two-ring, but since they're not sold in the UK they're a bit rare (and double the price of the one-ring).<br />

<br />

Ilkka - in my defence the conversation went something like "I'm not sure I trust this lens"/"are you sure you want to borrow it"/"it seems to be okay now I've programmed the lens data so long as you don't zoom it away from 200mm, but I suspect it's not happy" etc. If 200 f/2.8 gets her a shot in dim conditions and smaller apertures don't, it's better than nothing - and I'm not on for lending my 200 f/2 even if she could carry it. I should stress this isn't the only lens I leant her, my D700 isn't her only camera, she's only shooting the morning, and after the last wedding when she borrowed my camera kit she did say "never again". But then, <i>I</i> wouldn't like the stress of shooting a wedding at all. My conscience isn't entirely clear about the loan, but I've done my best to warn her...</p>

[Andrew Garrard]

<p>Michael - thanks. Regarding the AI/AI-S distinction, I was trying to be too clever for my own good: I believe the D700 can only meter in stop-down mode with AI lenses, but could meter in open-loop with an AI-S lens <i>in theory</i> (in that there's nothing stopping it working out where to move the aperture lever to). However, the D700, like most cameras except, I believe, the FA, F-501 and F4, has no way to know that the aperture is linear - unless the lens is also AF, in which case the electronic contacts would provide this information. I my vague musings I was trying to work out whether it was possible for the aperture to be behaving in a non-linear manner (as with an AI-but-not-AI-s lens) while the lens was claiming otherwise. But, unless the lens is weirdly broken, it's hard to believe that's the case.<br />

<br />

I wasn't expecting the aperture lock itself to do anything, but I wondered whether it was a sign of something else. Hard to know, of course. I didn't do enough experiments to confirm, but the metering is definitely <i>better</i> wide open - the sluggish aperture blades theory is a good one. I'll do some timing experiment when I get the chance; if it just needs lubing, maybe it's not an extortionate fix. Or maybe anything that involves pulling one of these lenses apart would take half a day...</p>

[JDMvW]

<p><em>Ash nazg thrakatulûk agh burzum-ishi krimpatul.</em><br>

Could this be the aperture <em>ring</em>?<em><br /></em></p>

[Andrew Garrard]

<p>:-) Could be, JDM. Clearly "ash nazg gimbatul" is about focus (and possibly zoom, which fits my theme).</p>

[Matt Laur]

<p>I thought maybe it translated to, "One aperture ring to rule them all."<br /><br />Nerd out, -ML</p>

[arthur_cargill]

<p>The "D" really doesn't add much, it lets you take pictures of yourself in the mirror with flash and successfully realizes you're further away and the flash output needs to be increased, non-D versions will not. Wouldn't it be funny if your test WAS actually taking pictures of yourself in the mirror using flash. There's a few other things the lens telling your flash how far away your subject is plays a roll, but I'm pretty sure without flash D has no use and even with it most often offers little advantage.<br>

<br />+1 on sticky aperture blades, I too think that's most likely the culprit.</p>

[Andrew Garrard]

<p>*Nod* - I knew "D" <i>shouldn't</i> make much difference, I just wondered if I was horribly confused! For what it's worth: I was pointing at something sunlit. Thanks, Arthur.<br />

<br />

At the risk of not remembering how my camera works, as a work-around until I get the lens serviced, is mirror lock-up going to help me - i.e. would I be right in thinking that the aperture lever is activated as part of the mirror moving rather than part of the shutter firing? I know the aperture lever is completely independent on the D3 series (you can hold down the DoF preview and adjust the aperture on the camera and watch the DoF change in the finder, something that doesn't work on the D700), but I'm not sure how the D700 is hooked up. If the aperture lever moves with the mirror, M-Up might give everything a chance to move before the shutter releases. I'm hoping that trying to shove a sticky aperture lever can't hurt my D700, for what it's worth.</p>

[wogears]

<p>All with gold rings doth not focus;<br>

Not all used gear is da bomb.<br>

Auctions and sales can be bogus;<br>

When lusting for lenses--be calm!</p>

[rodeo_joe1]

<p>Hi Andrew. I think one of two things might be going on here. My first guess would be a sluggish aperture operation in your lens. Try taking a manual exposure with the depth-of-field preview button pressed. This will (hopefully) ensure that the aperture is fully stopped down before the shutter goes off. If you find the exposure varies between preview depressed and preview not depressed, then the lens iris is suspect. This will be confirmed if automatic exposures tend to become more overexposed as the aperture is stopped down to its minimum. If wide-open exposures are always correct, then this can be taken as additional evidence pointing to a sticky iris.</p>

<p>Second guess would be the CPU in the lens. I've had some 3rd party AF lenses that simply refuse to give the correct exposure with my D700, despite the aperture mechanism apparently working OK. I really haven't got to the bottom of why this happens, but it appears that Nikon (bless them) have deliberately made the camera incompatible with all flavours of AF CPU, especially non-Nikon chips. This obviously shouldn't apply in this case, but who knows? In this case, consistently or randomly overexposed shots at any aperture would be commonplace.</p>

<p>The sticky iris problem could most likely be fixed by servicing the lens. The second problem has no cure except for pure manual metering and manual control of exposure AFAIK.</p>

<p>Addendum: The focal length of the lens in "non-CPU lens data" is pretty much irrelevant. I set a mid focal length for any MF zoom I use, and this works out fine. It's the maximum aperture that's important.</p>

[Andrew Garrard]

<p>Les: Well, it's better than Tolkien's poetry. :-)<br />

<br />

RJ: The DoF preview is a cunning plan. When I get my stuff back, I'll try it; I assume this <i>does</i> lock the aperture on a D700? (Just wondering how the cycle of the aperture lever works and whether cycling it once for DoF preview means that it needs to reset before taking an image - I don't really have a feeling for how everything is connected in a D700, but I know just enough to be nervous.)<br />

<br />

I wondered about the CPU, but the behaviour is very consistent. The fact that the focal length <i>does</i> seem to make an exposure difference when I set non-CPU lens data suggests that perhaps something thinks the lens is a variable aperture zoom where it's in fact constant... but my experimentation has been far from conclusive thus far; all I've really concluded is that something very weird seemed to be going on, and I was grasping at straws. I suspect the sticky aperture theory is more likely, but I'll give the contacts a clean anyway.<br />

<br />

Thanks for the feedback, everyone. I've got something to try when I get the lens back, even if it's just bracing myself for taking it to Nikon UK.</p>

[studio460]

<p>Arthur said:</p>

<blockquote>

<p>The "D" really doesn't add much, it lets you take pictures of yourself in the mirror with flash and successfully realizes you're further away and the flash output needs to be increased, non-D versions will not.</p>

</blockquote>

<p>OMG! That's funny!</p>

[Wouter Willemse]

<p>Andrew,<br>

Not entirely the topic, but well:</p>

<blockquote>

<p>I did see a little more bloom around contrasty edges than I might have expected</p>

</blockquote>

<p>I have the 2-ring AF-D, and it is not free of CA (at all); with high contrast edges, it is one of the few lenses I have that need additional correction in Capture NX2 to remove purple/blue edges. It does rob sharpness a little too, I think (though never enough to have me worry about it).</p>

<p>Have to run now to secure this lens.... I hear a few horses outside....</p>

[rodeo_joe1]

<p>Andrew, using the depth-of-field preview button does indeed leave the aperture stopped down if the shutter button is pressed, but strangely the lens opens up again immediately after the shutter/mirror cycle is finished.</p>

<p>To clarify, the sequence is: D0F preview depressed>lens stops down>shutter release operated while DOF is kept pressed>lens remains stopped down and shutter opens>shutter closes and lens iris springs open regardless of DOF button being pressed. The DOF button then needs to be released and pressed again to force the lens to stop back down, so this will only work for the first exposure of a burst sequence.</p>

<p>Use of the DOF preview button also locks the exposure at its full aperture reading, so this "trick" can be used in any exposure mode to ensure that a sluggish aperture is fully stopped down. All of which makes me wonder how it would be possible to use stop-down metering with the D700?</p>

[Peter_in_PA]

<p>I have nothing to add except that your thread title is totally BAWSS!</p>

[JDMvW]

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<td>

<p>From the Urban Dictionary<br /> <strong><em>bawss</em></strong></p>

</td>

<td id="tools_1932006"><a href="http://www.urbandictionary.com/define.php?term=bawss"><strong></strong></a><a href="http://www.urbandictionary.com/define.php?term=bawss"><br /></a></td>

</tr>

<tr>

<td><br /></td>

<td id="entry_1932006" colspan="2">An ebonics expression for a person who regularly baols out of control, derived from the English word boss. The word itself is an incredibly powerful and effective way to describe someone's demeanor or behavior, indicating that they represent the highest echelon of gangsta. For a better explanation, listen to Slim Thug's track "<a href="

a Boss</a>".</td>

</tr>

</tbody>

</table>