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Sun Marco Telephoto 2.8/135 (haze or reversed elements?)
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PostPosted: Sat Jan 29, 2011 4:50 pm    Post subject: Sun Marco Telephoto 2.8/135 (haze or reversed elements?) Reply with quote

I founded this is a rare lens so I bought it for to fullfill my curiosity.


This is the biggest 2.8/135 lens I ever owned with 62mm filter size. It goes to 1:3. Its quality is averge When focusing at distance objects but it will become a soft lens when focusing some near objects (at any aperture ). Update: members suggest this lens may suffer from haze or reversed elements, so the following photo may not be the acutal performance of this lens. Here are some photos from this lens(resize only).





Last edited by calvin83 on Sun Feb 06, 2011 3:05 am; edited 4 times in total


PostPosted: Sat Jan 29, 2011 7:21 pm    Post subject: Reply with quote

Looks like a lens without any coatings, a lot of flare. Hood should help with that. Also avoid photo situations where flare is difficult to control, such as back-lit scene.

The intensely bright yellow flower is over-exposed, detail is lost and 'blooming' (correct term? or glowing). I know I have to underexpose Dandelion 2 or more stops to prevent yellow over-saturation.

The general rule is "It's hard to make a bad 135". The results above could show here is a bad 135, but the problem is like to be with the optics, perhaps a reversed or loose element or group. If results don't improve dramatically in situation where flare is under control, the optics may have problem. The fly photo especially shows optical problem, see the leaf edges.


PostPosted: Sun Jan 30, 2011 1:07 am    Post subject: Reply with quote

I believe you have haze or fugus in the internal glasses. Please look through strong light or use flashlight to check.


PostPosted: Sun Jan 30, 2011 3:50 am    Post subject: Reply with quote

I agree, there is something wrong with this lens. This cannot be the intended result of the design. Sun made good, average and poor lenses, but never anything like this.

Even the worst lenses sold commercially should give better results.


PostPosted: Sun Jan 30, 2011 5:35 am    Post subject: Reply with quote

This lens is coated. I have sold this lens so I cannot check. Either the seller, the buyer and myself does not see any fungus or haze with this lens(I cannot sure if the lens has been cleaned). It may be caused by reversed elements? Here is two more photos which focus distance objects.



PostPosted: Mon Feb 07, 2011 7:51 pm    Post subject: Reply with quote

I got a request to post pictures here and these are convenient Smile

I found one after a member of PentaxForums made a thread with his findings--it's a cheap soft-focus lens. My version is a Sears 135mm f/2.8, 52mm filter, Pentax K mount, Model 202, Made in Korea. As you click to a high "macro" ratio, the front lens group moves further away from the body.

The lens does have a little bit of haze near the front...in fact, I believe it's on the back of the front-most glass. Thing is, though...there's no effect on the image viewed at 100-200% on the computer. The haze appeared in the last year or so...it wasn't there when I first got it.

The lens gets softer with more magnification...as in, the 1:5 setting is softer than 1:6, and 1:7 is noticeably sharper than 1:6. Working distance goes down by around 8" per click of the front element. In 1:5 mode, infinity is perhaps 10 feet away. In "normal" mode, above f/4, it's sharp as any 135mm.

First two images taken with the lens were from when I got it...I believe October 09...




Normal mode, f/22 (for a slow shutter Wink)


1:5 macro mode, probably minimum focus distance, f/4?


These are put through Camera Raw with the same settings for USM (33%, 2px, 0 threshold)...no exposure or other corrections, etc.

f/5.6 in 1:5 macro mode...I actually tried the same shot at f/16 and couldn't tell a difference on the computer screen...


f/8 or 11 in normal mode...


same f/8 or 11 in 1:6 macro mode...


So, I wonder what the engineers said when the marketers wanted a lens with "macro" function...built to a certain price point (Sears was a budget line, even though it was made by a build house). It's clear the performance is not really "macro" and the performance isn't really good, even Laughing A large-pixel USM tweak would probably take care of the halo effect.


PostPosted: Mon Feb 07, 2011 9:36 pm    Post subject: Reply with quote

My Makinon 135 2.8 is similar to the Sears, but I think it goes to 1:4 "macro". The macro ring is similar to the focusing mechanism in some folders, which uses the first element to focus, instead of moving the whole lens. This will cause some amount of uncorrected spherical aberration if the front element is not in the unique optimal position. This aberration can be minimize by stopping down.In the Makinon you can, at least at a certain extent, select the amount of softness by selecting the focusing method and the aperture.

In my lens you can focus using only the macro ring down to about 1,5 m. The softness is obviously more pronounced for closed subjects. It is very nice at 2.8 but IIRC much less at 4 and it disappears at 5.6. In "normal" mode (i.e. focusing using only the proper ring) the lens is very sharp even wide open. Curiously this lens (the Makinon) has deserved mixed reviews: some say it is junk and others tack sharp. I am from the latter group Smile

Javier


PostPosted: Mon Feb 07, 2011 11:21 pm    Post subject: Reply with quote

Very interesting observation. The lenses all move at the same time in the Sears, but only the front ones move when in macro mode. That would explain some of it, at least Smile

The Sears is the opposite of the Makinon in a couple ways...it doesn't get sharper with a smaller aperture opening in macro mode (at least not that I can tell). And, it's not very sharp wide open Confused Not a real problem when you want to use it as a "soft" lens...and f/4 is still pretty good Cool


PostPosted: Tue Feb 08, 2011 3:42 am    Post subject: Reply with quote

ryan s wrote:
Very interesting observation. The lenses all move at the same time in the Sears, but only the front ones move when in macro mode. That would explain some of it, at least Smile

The Sears is the opposite of the Makinon in a couple ways...it doesn't get sharper with a smaller aperture opening in macro mode (at least not that I can tell). And, it's not very sharp wide open Confused Not a real problem when you want to use it as a "soft" lens...and f/4 is still pretty good Cool

The Sun lens will be soft at every aperture when in marco mode. I think Sears has a similar focusing mechanism. Some version of Hanimex 2.8/135 goes to 1:4. It may come from the same lens marker as the Makinon.


PostPosted: Tue Feb 08, 2011 7:03 am    Post subject: Reply with quote

One to avoid! Shocked