Non-CPU Lens Data

[girishmenon]

<p>When using say, a Nikon 500mm f/4 AiS lens with a TC-301 on a D300/D200, should I key in 500mm f/4 or 1000mm f/8 as the non-CPU lens data?<br>

Thanks in advance! </p>

[Wouter Willemse]

<p>The Non-CPU data is mostly for your EXIF data (convenience) and to see the right aperture in your displays; it does not vastly change how things work otherwise. For example, if you accidentally select the wrong non-CPU lens, things will still work properly and the meter reading will not be off (not more than usual anyway).<br>

So, you can do what you find the most convenient.</p>

[rodeo_joe1]

<p>I think I'm right in saying that modern AF/CPU teleconverters don't electronically translate the lens aperture to the effective aperture. So it's fine to enter the aperture and focal length of the unconverted lens. However, by entering the converted focal length and aperture the EXIF data will be more correct and you'll be able to tell that a converter was used.</p>

<p>Personally I'd enter the converted values for aperture and focal length, since you'll then get a reminder in the viewfinder of the real aperture in use.</p>

[Wouter Willemse]

<blockquote>

<p>I think I'm right in saying that modern AF/CPU teleconverters don't electronically translate the lens aperture to the effective aperture</p>

</blockquote>

<p>It doesn't change anything for the answer for Girish, but I think your statement is actually wrong. When I use my TC14E or TC17E, the displayed aperture changes, and in EXIF data the focal length is changed, and it shows the corrected aperture. The lens displayed, however, will not be changed (so, for example, it'll show I used the 300 f/4D, focal length: 420mm).</p>

[rodeo_joe1]

<p>Thanks for that info Wouter. My only experience with AF converters is with 3rd party and Nikon ones that are now a bit dated, and they certainly don't change the basic lens data transmitted to the camera. I have no experience with, nor use for Nikons 'E' version converters at present.</p>

[BelaMolnar]

<p>All the cameras measure light true the OPEN LENS, regardless what you set in the non CPU lens data. Those Lenses which has no electronic connection, has no electronic data to transfer to the cameras computer, The "Non CPU lens set up" only, for your information and a limited data to the exif file. The only lens - camera connection is the mechanical lever for the aperture, and you has to change aperture setting manually on the NON CPU lens or called non AI or AI-S lenses. The camera sensing the set aperture with the physical AI connection tab nor lever. If your manual lens is old and no AI lens coupling, but, by converting "mechanically" the lens to AI, the camera has the ability to know the set aperture. During the exposure, inside the camera, close to the lens , has a coupler the lever which closing down the lens preselected aperture at the moment, when you releasing the shutter. Basically, the camera is "M" manual, and you has to operate the camera manually, focus, aperture and light-meter. A hard stuff for the guys whom born with a total automatic DSLR cameras in they hand. Otherwise, very easy for the experienced. Most of my lenses AI, AI-S or AI converted lenses, and it is a joy to use them.</p>

[girishmenon]

<p>Thanks for all your replies : )</p>

[scott_murphy5]

<blockquote>

<p ><a name="00cyoZ"></a><a href="/photodb/user?user_id=831118">Bela Laszlo Molnar</a> <a href="/member-status-icons"><img title="Subscriber" src="/v3graphics/member-status-icons/sub10plus.gif" alt="" /><img title="Frequent poster" src="/v3graphics/member-status-icons/3rolls.gif" alt="" /><img title="Current POW Recipient" src="/v3graphics/member-status-icons/trophy.gif" alt="" /></a>, Nov 28, 2014; 02:12 p.m.</p>

</blockquote>

 

<blockquote>

<p>All the cameras measure light true the OPEN LENS, regardless what you set in the non CPU lens data.</p>

</blockquote>

<p>All 14 of my lenses are mf prime AI/AIS and I almost <em>never</em> bother with entering the non-CPU data on my D700. I change lenses frequently depending on the situation and it is just too much trouble. As you say, the metering system bases exposure on what it sees not what you have set in the camera. </p>