Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Lens haze effect on picture quality
Post new topic   Reply to topic
Home   Manual Focus Lenses
View previous topic :: View next topic  


PostPosted: Sat Aug 22, 2009 3:18 am    Post subject: Lens haze effect on picture quality Reply with quote
I've got a Vivitar S1 135/2.3 with haze on the rear element. Fortunately, it was an easy clean (the rear element is a 'floating' one, so it came off right away with the mount). Just wanted to post two images taken with this lens before and after the clean. Same time of day (around 13:30), same lighting conditions, same subject... only the second image is taken after the lens has been cleaned. The difference in contrast is quite dramatic, yet there is no discernible effect on sharpness. No post processing applied!

Haze:


No haze:


PostPosted: Sat Aug 22, 2009 3:58 am    Post subject: Reply with quote
that would be what i'd expect .... haze would decrease contrast due to scattering of light from the hazed surface, but it would have no effect on sharpness because it doesn't change the shape of any of the refracting surfaces of the lens.


PostPosted: Sat Aug 22, 2009 6:21 am    Post subject: Reply with quote
congrats, you clean it fast; sun barely move in between
many prefer low contrast lens and fix it in post processing
that could be the solution; to put some haze on the rear element


PostPosted: Sat Aug 22, 2009 7:07 am    Post subject: Reply with quote
poilu wrote:
congrats, you clean it fast; sun barely move in between
many prefer low contrast lens and fix it in post processing
that could be the solution; to put some haze on the rear element


LOL, it took me a day to figure out what to do (or, rather, what not to do), so the sun is, indeed, at similar positions. I didn't want to mess around with levers and springs and ball bearings... so spent some time researching and asking questions.

Apparently, this lens features a special 'floating' element designed to correct for its close focusing ability (MFD 0.9m). This element gets haze often, as the main optical unit moves air right onto it. If the lens gets hot, the lubricant vaporizes, and this 'floating' element is the only place it can condensate. Fortunately, this piece of glass is not connected to the main optical unit, and is instead attached to the lens mount. This, in turn, makes it an easy fix. Took me 5 minutes of work after a few hours of reading and emailing.

As to haze being a solution to lower contrast, consider this: haze does not add meaningful detail to the image. It simply shifts your black point to the right. When processing, if you move the black point, you are compressing the tonal range, losing smooth color gradation.


PostPosted: Sat Aug 22, 2009 7:54 am    Post subject: Reply with quote
Out of curiousity, how did you clean off the haze? A couple of cheap Ebay buys I have are in need of haze removal.


PostPosted: Sat Aug 22, 2009 8:55 am    Post subject: Reply with quote
xjjohnno wrote:
Out of curiousity, how did you clean off the haze? A couple of cheap Ebay buys I have are in need of haze removal.


I use isopropyl alcohol. However, I ordered some of this, just in case: Click here to see on Ebay ROR - Residual Oil Remover.

Note that not every type of haze is removable. If the haze is inside of a cemented element, you are SOL. Sometimes, coatings deteriorate; this haze can only be removed with the coatings.

However, more often than not, haze is just oil condensation, and is easy to remove once you have access to the hazed surface.


PostPosted: Sat Aug 22, 2009 1:27 pm    Post subject: Reply with quote
Aoleg: Well done!!

Enjoy your new "clean" lens.

Another haze lens? Haze inside the glass element because the tension of the different mass of glass as a defect of making process. The glass isn't homogenous. Not solution!!

Rino


PostPosted: Sat Aug 22, 2009 4:53 pm    Post subject: Reply with quote
I like background on the first one more Smile High-contrast subject on low-contrast background would be perfect Smile


PostPosted: Sat Aug 22, 2009 8:47 pm    Post subject: Reply with quote
pirius wrote:
I like background on the first one more Smile High-contrast subject on low-contrast background would be perfect Smile


A proper lens design (I've seen some Voigtlanders do it) can achieve contrasty in-focus and low-contrast OOF areas. Haze, soft filters etc. are not the right way to do it though. They don't add detail to an image, but simply shift the black point.


PostPosted: Sat Aug 22, 2009 11:58 pm    Post subject: Reply with quote
aoleg wrote:
pirius wrote:
I like background on the first one more Smile High-contrast subject on low-contrast background would be perfect Smile


A proper lens design (I've seen some Voigtlanders do it) can achieve contrasty in-focus and low-contrast OOF areas. Haze, soft filters etc. are not the right way to do it though. They don't add detail to an image, but simply shift the black point.


Yes, I've seen Zeiss and Leica lenses to do the same. I think that's what adds to their mysterious 3D effect.
Post new topic   Reply to topic
Home   Manual Focus Lenses
Page 1 of 1