What the heck is this??

[mountainrivera]

I shot this with the Zeiss ZM 25mm on my M240 using a flash. It looks like most of the pics I shot with the lens had this. On the same night I switched off with the 50mm asph and the pice were fine. I had the lens detection on auto (forgot to manually set it). I thought that may have been why but today I tried to duplicate the effect but the lens behaved normally. Anyone ever see this - lower right side of the pic?

 

[Brian Legge]

First guess would be flare from light in the upper left? Was the ceiling bright enough to reflect a moderate amount of light?

 

[mountainrivera]

Thanks: It was a fairly low ceiling and I bounced the flash. It happened pretty consistently with the Zeiss only. If it were a defect in the sensor I would think it would happen all the time. Perhaps it is the way the lens handled the flash in that location.

 

[RandyB]

Looks like there are lots of things on the table that can reflect speculair light back into the lens causing a flare. It may be outside the sensor area but still causing a diffraction of the reflection causing the rainbow flare. Even bounced light can cause a flare under the right conditions. Just a thought

 

[willie_901]

This ghosting is almost certainly due to simple bad luck. Artifacts from reflections are extremely sensitive to the angle of the reflected light. This explains why you could not duplicate the ghosting.

I was wondering if you used a lens filter. In rare cases reflections between the sensor glass cover and a lens filter can generate ghosting artifacts.

 

[mountainrivera]

Hi and thanks for the posts. I did not use a filter. It did happen in a majority of the shots I took that night with the lens in different locations in the hall. It was the first time I used the lens outside of two-three test shots. Edited to add pic. I just took a few test shots with both the zeiss and the 50mm summilux with flash and the Zeiss seems to do this consistently see lower right(%^&%!!!) Here is a sample.

 

[mountainrivera]

OK, more test shots in doors. Consistent with a flash, fine without. I think I'll shoot a note to Dag and see what he thinks.

 

[kanzlr]

reclection of sensor glass stuff whatever?

or wrong shutterspeed for flash use?

 

[sevo]

Shutter speed too fast - the shutter has already closed by one or two mm when the flash is triggered. That seems to be a pretty common issue from the M9 on. 1/180s is a bit euphemistically calculated, it has no margin for any extra delay from the flash itself. Use 1/125s and you should be fine.

 

[willie_901]

Shutter speed too fast - the shutter has already closed by one or two mm when the flash is triggered. That seems to be a pretty common issue from the M9 on. 1/180s is a bit euphemistically calculated, it has no margin for any extra delay from the flash itself. Use 1/125s and you should be fine.

Bingo!

I did not even see this band on the first photo because the ghosting seemed atypical to me.

Changing the subject, I think your flash is at least a 1/2 stop (maybe more) too strong in these images. Perhaps this is the look you're going for...otherwise less is more when bouncing flash light indoors.

 

[mountainrivera]

Shutter speed too fast - the shutter has already closed by one or two mm when the flash is triggered. That seems to be a pretty common issue from the M9 on. 1/180s is a bit euphemistically calculated, it has no margin for any extra delay from the flash itself. Use 1/125s and you should be fine.

I thought for sure this would do it but unfortunately it did not. I went to 1/90. Very frustrating.

 

[_goodtimez]

Apart from the flare there seems to be a lot of distortion on the bottom of the first picture. Is this normal for the Zeiss ?

 

[mountainrivera]

More testing: I have a Contax TL 140 no bounce and it did not exhibit the flair. I had these bad results using a small panasonic with a tilt head by the way and I tried it with no bounce and it seemed to diminish but not fully. I then tried it with the behemoth vivitar 285vh and saw very slight banding if underexposed and nothing if correctly exposed. So, it seems as if the panasonic's light trajectory is exploiting something - what I have no idea!! BTW, here is the full first pic with the crap cropped out:

 

[sevo]

So, it seems as if the panasonic's light trajectory is exploiting something

Nope, it is the electronics. That flash is particularly slow to respond.

If you want to test what exposure time a flash requires, test with exposure times from at least 1/60 to 1/250 and some subject with a foreground only illuminated by the flash and a daylight illuminated background. In that setting, the foreground will develop a easily visible black bar at the bottom, proportional to the amount the flash triggers late. 1/250s is the check value - the curtain MUST obscure at least three of four mm of the flash-exposed area at that setting.

 

[mountainrivera]

Thanks for all the great info. It just seems odd to me that I have no issues with my 50mm 'lux asph. Shouldn't the flash also behave badly with that lens also?

Nope, it is the electronics. That flash is particularly slow to respond.

If you want to test what exposure time a flash requires, test with exposure times from at least 1/60 to 1/250 and some subject with a foreground only illuminated by the flash and a daylight illuminated background. In that setting, the foreground will develop a easily visible black bar at the bottom, proportional to the amount the flash triggers late. 1/250s is the check value - the curtain MUST obscure at least three of four mm of the flash-exposed area at that setting.

 

[mountainrivera]

OK, so just shot some pics with the vivitar at 1/180 and no issues. Chalking it up to the panny flash. You guys have been awesome. Thanks for the time and advice!

 

[willie_901]

Thanks for the update.

With regard to ghosting, the Zeiss ZM 25mm lens' wider field of view means ghosting is more likely. I have noticed this with other lens/camera combinations. The Nikkor 24/2.8 AIS was exceptionally prone to ghosting compared to the Nikkor 50 mm AFS and G lenses. This was true for both the F3HP and D200/300/700 bodies. The Nikkor 12-24/4 AFS DX zoom was a real problem at focal lengths below ~18 mm.

I don't see how lens selection could affect the band at the bottom of the frame caused by shutter/strobe syncing artifacts.

 

[sevo]

I don't see how lens selection could affect the band at the bottom of the frame caused by shutter/strobe syncing artifacts.

Aperture and focal length can affect that, as they determine how blurred the curtain shadow will be - a fast lens shot wide open might not show enough hard edge to create a obvious band.

 

[willie_901]

Aperture and focal length can affect that, as they determine how blurred the curtain shadow will be - a fast lens shot wide open might not show enough hard edge to create a obvious band.

Interesting!