Katzeye, D200 and 18-200

[Dennis]

Anybody have the above combi ?.
Although stated at katzeye web site that it will over expose in spot metering.
I find this unusual. tested with many other lens and the overexposure for spot metering is pretty controlled and OK, sometimes even negligible.
But with the 18-200 the overexposure for spot metering at the tele end is about 2-3 stop ??. wide end is OK. Other metering like matrix and center weighted are OK.
Any reason for it ??.

 

[ExplorerZ]

it depends on where the spot is at... if it is on a very dark area, those brighter part of the picture will definitely get overexposed. but if it is on a average exposed area of the pic. i doubt it will overexposed.
For spot metering the main idea is to know where you are trying to metering at...

 

[Dennis]

Yes I know that but the meterings are ok on other lens but not on the 18-200.
I have been putting off the Katzeye for some time because I use spot metering quite extensively. i.e. I tested it on a 70-200 at 200 and the 18-200 at 200 but the metering for the 70-200 is Ok but not the 18-200. I know the aperture plays a part but does super zoom plays a part as well ?. Actually I also tried on a 24-120 but is is not as bad as the 18-200. Other lens like the 17-55, 18-70, 50mm, 45mm, 105mm etc all tested quite OK.

it depends on where the spot is at... if it is on a very dark area, those brighter part of the picture will definitely get overexposed. but if it is on a average exposed area of the pic. i doubt it will overexposed.
For spot metering the main idea is to know where you are trying to metering at...

 

[espn]

Dennis, only your 18-200? Your other DX glasses all the same? Might be the Katzeye doesn't work well with DX, esp at the tele-end, probably in this case a 200DX? Just a guess.

 

[Dennis]

Tried with other DX but seems OK, tried 24-120 seems like the overexposure is bigger than others but not as wide as the 18-200. I suspect because of big zoom range ??.
Will do further test to see once I have the time. Now enjoy it first lah just try compensating loh. However I think a 2-3 stop compensation is too much b ut once you know what to compensate it is OK.

Dennis, only your 18-200? Your other DX glasses all the same? Might be the Katzeye doesn't work well with DX, esp at the tele-end, probably in this case a 200DX? Just a guess.

 

[espn]

Tried with other DX but seems OK, tried 24-120 seems like the overexposure is bigger than others but not as wide as the 18-200. I suspect because of big zoom range ??.
Will do further test to see once I have the time. Now enjoy it first lah just try compensating loh. However I think a 2-3 stop compensation is too much b ut once you know what to compensate it is OK.

Try with your 70-200VR? I initially thought it's a problem with DX tele-zooms. But your 24-120VR also? :dunno:

 

[Dennis]

70-200 seems OK, 24-120 have the same problem but not as serious.
Not sure what is wrong but I wrote to Katzeye pending their reply.
I thought the exposure should be quite consistant over the whole range of lens.
Other DX lens 17-55 and 18-70 tested is OK.
Can be either the aperture is small as all others seems OK and the wide side seems OK.
Have not tested with my 500 cat yet, if it is because of aperture than the 500mm cat should be the same.
Read somewhere that it only affect the centre spot if use other area it is OK but have not tested it out yet.

Anybody have the same combo to test it out ??.

Try with your 70-200VR? I initially thought it's a problem with DX tele-zooms. But your 24-120VR also? :dunno:

 

[Dennis]

OK here's the reply from Katzeye, seems like I have to live with it.
It seems to coincide with my test as well.
Tried with a 500mm cat f8 and the result is the same.
Tried with a 70-200 + 2x TC the result also gives more overexposure than necessary.
The 2-3 stop I encounterd with the 18-200 at the long end is consistent with their 2.5 EV increased in exposure.
Guess I did not anticipated that the increased in exposure to be relative with the increased in max metering aperture but having said that it seems to taper off from f5.6.
In short anything above f3.5 will gradually have increased in exposure up to maybe 3 stop.
Still recommended for those who wants it. Just understand the spot metering exposure index with your favorite lens. :sweatsm:


Reply from Katzeye

This all sounds pretty normal for spot metering. As stated on the website,
you can expect metering shifts in spot mode with lenses f3.5 or slower.
What matters is the maximum (metering) aperture of the lens. The focal
length is of little effect. In spot mode, I would expect the 18-200 to show
anywhere from 1 EV increased exposure at the wide end to 2.5 EV increased
exposure at the long end. The 85mm and 50mm should give accurate metering
results. The 17-55mm will probably show about 1/2 EV increase; but since
the camera underexposes normally, it shouldn't be a problem. The 18-70mm
will show increases varying from 1 EV at the wide end to 1.5 EV at the long
end. The 24-120mm should behave about the same as the 18-200mm, since they
have the same maximum aperture.

As far as how to deal with this, you have two choices. Your first option
would be to take some test shots, read your histograms and use some negative
exposure compensation. It might help to make yourself a little crib sheet
that gives you the necessary exposure correction for each lens. Your other
option would be to use a different metering mode with the lenses that are
f3.5 or slower. I've heard that it's also possible to use an off-center
focus point to take a meter lock, then change the focus point and recompose
before taking the shot. But I've not tried that technique personally. For
myself, I either take a test shot and dial in negative EC or I just switch
to centerweighted metering when I'm using a slow lens.

 

[Artosoft]

Dennis,

From KatzEye explanation, do you have tried:
- Use different point of focus (off-centre point)?
- Use other than spot metering (ie.: centerweight)?

I appreciate your finding report on above.

Anyone know will KatzEye give the same exposure problem on D70s? I am considering to have it, but if too much exposure problem, I will think twice.

Thank you in advance.

Regards,
Arto.

 

[Dennis]

Have yet to really try different point of focus as I am so used to spot in the centre but will give it a go when I have the time.
Using any other metering option seems OK except spot.

Dennis,

From KatzEye explanation, do you have tried:
- Use different point of focus (off-centre point)?
- Use other than spot metering (ie.: centerweight)?

I appreciate your finding report on above.

Anyone know will KatzEye give the same exposure problem on D70s? I am considering to have it, but if too much exposure problem, I will think twice.

Thank you in advance.

Regards,
Arto.