 |
|
| View previous topic :: View next topic |
| Author |
Message |
Henry Fisher

Joined: 11 Oct 2008 Posts: 21 Location: USA
|
Posted: Sun Feb 07, 2010 7:03 pm Post subject: Multicoated, Single Coated, Uncoated -- And dSLRs |
|
|
Hello Forum.
I would like to open a discussion about the use of older optics in front of modern digital sensors. The reason is that I am reading conflicting information in this respect, and I would like it sorted out by the Membership here who may have experience in this respect.
More than a few have said that digital sensors are reflective, and as such, they require optics that have improved anti-reflective coatings. Some have said that superior coatings designed to address this issue are a key ingredient it what it is that constitutes so called "digital lenses."
Recently, I read a thread on nikonians.org wherein a gentleman said that he did not recommend Nikon's series E lenses for digital sensors because they were only "single coated."
Are you using older lenses with single coatings or with no coatings with your dSLR? Are you pleased with their technical performance? Do you have problems with flare or internal reflections which are leading you towards upgrading to only "digital" lenses?
I am particularly interested inasmuch as I intend to us a lot of old Nikon and other F mount manual focusing glass on a D700. So far, I am not seeing the problem. One of my lenses is a 50mm f1.8 Series E, of the sort that the nikonians.org gent "does not recommend." It seems to have no problem whatsoever, as far as I can tell. What am I missing in this analysis? The pictures look good to me.
Are there special limitations or precautions one should consider when one is using old glass on new digi bodies?
Thanks for reading this, and for the courtesy of your response.
Happy day.
 _________________ Henry
A certified dinosaur using F, F2, D700, M3, Kiev 4a
"I think there's some sense of magic in the fact that what's out there can be caught in this little box." ~ John Loengard
Last edited by Henry Fisher on Mon Feb 08, 2010 6:29 pm; edited 1 time in total |
|
| Back to top |
|
 |
Spotmatic


Joined: 18 Aug 2008 Posts: 2097 Location: Netherlands
|
Posted: Sun Feb 07, 2010 7:26 pm Post subject: |
|
|
I can only tell about my own experiences, and I have used several lenses from 1896 up to today. Most of my lenses are single-coated and some of them not even coated, and I'm not seeing any problems either. Of course, most of my uncoated prewar lenses are low contrast because of light shattering in the lens, but nothing that can't be corrected in PP.
A good modern example is my Sigma 500mm f/4.5 APO EX. Apparently there's an updated version available with "DG" in its name because it has a "special" digital coating. Well, my shots with the non-DG lens are nothing short of superb, so I don't feel the urge to upgrade just for a "better" coating.
Mind you: I don't say that the problem does not exist, just that I don't see it. Let's reserve this discussion for people who never take photographs, but only talk about it  _________________ "Old Takumars never die; they just fade away"
Pentax K-7 + Pentax 645 + Bessa RF 10,5cm Heliar, Bessa II Apo-Lanthar and a 'little' bag full of MF lenses. The lens list is * here *.
My fast 80s: Asahi-Kogaku Takumar 83mm f/1.9 - Super-Takumar 85mm f/1.9 - S-M-C Takumar 85mm f/1.8 - FA 77mm f/1.8 Limited - Cyclop 85/1.5 (Helios-40 innards) - Komura 80mm f/1.8 - Komura 85mm f/1.4 - Accura Supertel Tc 1:1.9 f=85mm - Jupiter-9 2/85 - Meyer Görlitz Primoplan 7,5cm 1:1.9 - Carl Zeiss Jena 75mm f/1.5 Biotar - Carl Zeiss Jena 80mm f/1.8 Pancolar - Canon 85mm f/1.8 S.S.C. - Canon 85mm f/1.2 S.S.C. Aspherical - Enna München Ennalyt 85mm f/1.5 - Olympus Zuiko Auto-T MC 85mm f/2 |
|
| Back to top |
|
 |
cooltouch


Joined: 15 Jan 2009 Posts: 1448 Location: Houston, Texas
|
Posted: Sun Feb 07, 2010 7:40 pm Post subject: |
|
|
Well, bearing in mind that I'm commenting based on my own experiences, and to some extent on what I've read, here's my take on things:
Yes, "digital lenses" have coatings as well as internal baffling in some cases designed to deal with the stray reflections that can degrade the image. But I suspect that rear element shape also is mixed into the equation.
For instance, it has been pretty well documented that the Tamron SP 90mm f/2.5 Macro (models 52B and 52BB) causes a hot spot to appear in the center of the image with many DSLRs. I have confirmed this with my own Tamron 52B and my Canon XS. But in the case of my lens and camera, this hot spot is a rather minor one, only beginning to show once I've stopped the lens down to about f/8 or so. So, as long as I shoot with the lens fairly wide open, I'm okay.
Now the reason that has been cited for this problem with the Tamron is it has a flat rear element, which is the culprit.
I also have used quite extensively a mid-1960s vintage 55mm f/3.5 Micro-Nikkor lens with my XS. This lens is not multicoated, but I have not had a bit of problem with reflections degrading the images at all.
I also own a Century Precision Optics 500mm f/5.6 telephoto lens that also dates back to the 1960s, which I've used quite a bit with my Canon XS. It isn't multicoated, either. The pair take amazingly sharp photos. No image degradation whatsoever.
In the case of the Micro-Nikkor and the CPO 500/5.6, both have recessed front elements -- the Micro because of its lens design, and the CPO because of its integral hood. The fact that the front elements are hooded probably allows for some improved contrast, but they will have no effect in lighting conditions where the sun is not directly visible.
Bottom line, I would not pay too much attention to the opinions of others. Too many folks take it upon themselves to present "expert" opinions based only on their assumptions and not real data.
Here at mflenses, you'll have the opportunity to inquire about lenses that people have used with their DSLRs, and who can provide you with real-world data. Which is why this forum is so useful.
So, if you are enjoying good results with a lens, like your 50mm Series E, then it, by definition, works well with your setup. And you have just passed along this useful bit of information to the rest of us here. Backing up your observations with photographs is always helpful and welcome as well. _________________ Michael
Check out my Photo Blog: http://michaelmcbroom.com/blog/?cat=4
Canon FD: F-1n, FTbn, AE-1P, Canon Power Winder A, Canon Power Winder F, Sportfinder F, Vivitar 17mm f/3.5, Vivitar 35mm f/1.9, 50mm f/1.8, FL 55mm f/1.2, 85mm f/1.2 SSC Aspherical, 200mm f/4, 35-105mm f/3.5, Vivitar 200mm f/3.5, Vivitar S1 24-48mm f/3.8
Canon EOS: Elan IIe, XS (1000D), EF-S 18-55mm f/3.5-5.6 IS, 28-80mm f/3.5-5.6 IV USM, 70-210mm f/4, 75-300mm f/4-5.6 II USM, Tamron 24-70 f/3.3-5.6 Aspherical, 420 EZ strobe
Canon Rangefinder: IIIa, Serenar 50mm f/1.8
Nikon F: F2 w/MD-2/MB-2, 24mm f/2.8, 28mm f/2.8, 35mm f/2, 50mm f/1.4, 55mm f/3.5 Micro, 105mm f/2.5, 80-200mm f/4.5, Vivitar Series 1 28-90mm f/2.8-3.5, Vivitar Series 1 105mm f/2.5 Macro
Olympus: XA, OM-10 w/Manual Adapter, 50mm f/1.8
Pentax K:KX, MV, 50mm f/2 SMCP, Kalimar 28-200mm f/3.9
Fuji: Finepix S3000 3mp digicam
Tamron Adaptall: 24mm f/2.5, SP 90mm f/2.5 Macro, 35-80mm f/2.8-3.5, 80-210mm f/3.8-4, SP 60-300mm f/3.8-5.4, SP 1.4x, SP 2x
T-Mount: Century Precision Optics Tele Athenar 500mm f/5.6 and 650mm f/6.8
Medium Format: Bronica ETR-Si, 75mm f/2.8, Prism Finder E, Grip E, 120 & 220 backs; Yashica 124
Other Stuff: Spiratone Telescope eyepiece adapter (converts T-mount lens to telescope), Cambron zoom slide duplicator (T-Mount), Opteka Digital Slide Duplicator
Strobes: Metz 60 CT-1, Braun F900, Vivitar 285, Yashica Pro-50 DX, Yuzo DC2814 Ring Light |
|
| Back to top |
|
 |
F16SUNSHINE


Joined: 20 Aug 2007 Posts: 4431 Location: Anacortes Washington
|
Posted: Mon Feb 08, 2010 1:41 am Post subject: |
|
|
Multi coating will always give the best results in terms of Contrast, Saturation, and Color.
But what if you want low contrast or saturation. Or colors on the muted side for that matter.
Getting to know what to expect from different lenses will help improve any photogs ability to "make" the image that you want.
Try a some and see for yourself. There is really no best if it's not what you need for the situation.
I often will use a single coated lens when shooting B+W film as it seems to improve shadow detail. These is the case even though I have lenses with the very "best" modern coatings.
BTW A hood on a lens will always improve results performance more than late stage coatings. _________________ Dog is my copilot
 |
|
| Back to top |
|
 |
Henry Fisher

Joined: 11 Oct 2008 Posts: 21 Location: USA
|
Posted: Mon Feb 08, 2010 8:20 am Post subject: |
|
|
.
Thanks, Guys, for those thoughtful responses.
As noted, there are doubtlessly some self-appointed experts who are not really close to the problem, but who may be mouthing bits and pieces of things they have read somewhere, or some such. I agree that it is a much better idea to test individual lenses, and let this forum serve as a clearing house for information about what actually works and what does not.
The MF lenses I will be checking out are as follows:
Nikkors 24f2.8, 28f3.5, 35f2.8, 35~105f3.5, 43~86f3.5, 50f1.4, 50f1.8, 105f2.5, 135f3.5, 200f4, 500f8r, and a Kiron 80~200f4.
I found the idea about the flat rear element to be an interesting one. I will be looking for a correlation between that and the sensor, if I have any such lenses.
It is refreshing to find such seasoned and expert help as is available here. Needless to say, I am honored to be in your company.
Happy day.
 _________________ Henry
A certified dinosaur using F, F2, D700, M3, Kiev 4a
"I think there's some sense of magic in the fact that what's out there can be caught in this little box." ~ John Loengard |
|
| Back to top |
|
 |
aoleg


Joined: 22 Feb 2008 Posts: 548 Location: Canada
|
Posted: Mon Feb 08, 2010 9:27 am Post subject: |
|
|
The issue of single vs. multicoating has been debated before. MC sure helps boost contrast and saturation, but it is not the only factor, and not even the most important one.
First, there's lens design. The more air/glass surfaces a lens has, the more important is multicoating. Old designs such as Sonnar were made to minimize the number of air/glass surfaces by combining elements into groups. Nikkor-Q, Nikkor-Q.C., and the 'K' version of 135/3.5 were Sonnar designs with 4 lens elements in 3 groups. As such, coatings did not affect contrast much. Similarly, Sonnar-based Nikkor-P 105/2.5 (silver-nose) is 5 lenses in 3 groups; it gives excellent contrast even in the shadow.
Second, it's blackening of lens edges and baffling/matting of internal surfaces. Unfortunately, many lenses, especially in the USSR and Russia, were built without due care in this respect. I have a fully multi-coated Jupiter-9 that has LOWER contrast than a single-coated version made 30 years before it. This is because this lens was mass-produced and assembled without properly blackening edges of lens elements; disassembling the lens completely and painting each lens edge with matte black paint improves contrast dramatically. Similar problems were noted with many other Soviet and Russian lenses, especially telephoto ones (wide-angles are surprisingly flare-resistant even in single-coated variants, e.g. Mir-10A).
Finally, it's cutting stray light from the back of the lens. Stray light can reflect inside the camera tunnel, causing loss of contrast and over/underexposure.
| Henry Fisher wrote: | The MF lenses I will be checking out are as follows:
Nikkors 24f2.8, 28f3.5, 35f2.8, 35~105f3.5, 43~86f3.5, 50f1.4, 50f1.8, 105f2.5, 135f3.5, 200f4, 500f8r, and a Kiron 80~200f4.
|
The 24/2.8 and 28/3.5 are great lenses, yet I highly recommend getting muli-coated versions. For wides, MC really matters as hoods are largely ineffective. 35/2.8 is reportedly so-so; I've got the 2.0 version instead, and it's quite good.
I would not bother with early versions of 43-86 (I am selling one, as well as Nikkor-Q 135/3.5; PM if you're interested). Early pre-Ai 43-86's were rather mediocre in performance (yet, IMO, still better than some 18-55 kit lenses ) Ai and later versions are reportedly OK.
Both 50mm are great, the 1.4 is the better one of the two.
105/2.5 is classic design, available in Sonnar-type (pre-Ai, white nose, only available single-coated; very nice), and later Xenotar-type (available MC, which I'd get just to have the best pictures possible).
135/3.5 were also available single and multi-coated (Sonnar type), and MC only (Ernostar type). Depends on what you need...
200/4 were really much improves in Ai and Ai-S compared to pre-Ai, so getting a MC version is the only reasonable option. _________________
Canon EOS: 5DmkII, 24-70/2.8L, 70-200/4L, 85/1.8, Tokina 100/2.8 Macro, Kenko Pro TC 1.4x
Leica R: Elmarit 180/2.8 2nd gen, Telyt 250/4 1st gen
Nikon F: Ai 24/2.8, Ai-S 24/2.8, Ai 28/3.5, Ai-S 35/2, Ai 50/1.4, Ai-S 50/1.8, Ai 50/2, K 85/1.8, Ai'd K 85/1.8, Ai 85/2, Ai-S 85/2 x2, Series E 100/2.8 x2, P 105/2.5 (silver, 6 & 9 blades) x3, K 105/2.5 x2, Ai 105/2.5, Ai-S 105/2.5 x2, micro 105/2.8, Q.C. 135/3.5, K 135/3.5, Ai 135/3.5, Ai-S 135/2.8, Ai 180/2.8, ED 180/2.8, Ai 200/4, ED IF 300/4.5, pre-Ai 43-86/3.5
Olympus: MC 50/1.4
Pentax M42: S-M-C Takumar 28/3.5, SMC Takumar 50/1.4, Super Takumar 55/2, Super Takumar 135/2.5 (late with SMC coatings), S-M-C Takumar 135/3.5, Super Takumar 135/3.5, Super Takumar 150/4, S-M-C Takumar 200/4
Pentax K: SMC-M 50/2
Rollei QBM: Rolleinar 85/2.8
Russian: MC Zenitar 16/2.8, MC Peleng 17/2.8, Arsat-H 20/2.8, Mir-10A 28/3.5, MC Zenitar 50/1.9, MC Helios-77M-4 50/1.8, MC Volna-9 50/2.8, MC Industar L/Z 50/2.8, Helios-44M-4 58/2, Arsat-C (Volna-3) 80/2.8, Helios-40-2 85/1.5, Jupiter-9 85/2.8 (M39), MC Jupiter-9 85/2.8, MC Kaleinar-5N 100/2.8, Tair-11A 135/2.8, MC Jupiter-37A 135/3.5 x2, Jupiter-6-2 180/2.8, 16OKC7-200-1 200/2.8 (Kinor 16)
Yashica ML: 28/2.8, 35/2.8, 50/1.9, 50/1.9c, 50/2 x2, 35-105/3.5-4.5
Zeiss/Contax: Sonnar 85/2.8, Planar 85/1.4, Sonnar 135/2.8, Sonnar 180/2.8
Zeiss Jena: MC Flektogon 50/4, MC Sonnar 180/2.8, MC Sonnar 300/4
Mirror optics: Yashica ML Reflex 500/8, RMC Tokina 500/8
Third party: Samyang 85/1.4, Vivitar Series 1 35-85/2.8, Vivitar Series 1 135/2.3, Vivitar Macro Focusing 2xTC (7 elements)
Other stuff: Hanimex 105/2.8 pre-set (Tokina), Prinz Galaxy 135/3.5 pre-set (Tokina), another Prinz Galaxy 135/3.5 pre-set (Sankyo?)
www.prime35.com |
|
| Back to top |
|
 |
Orio

Joined: 24 Feb 2007 Posts: 18159 Location: West Emilia
|
Posted: Mon Feb 08, 2010 10:10 am Post subject: |
|
|
It's not only a matter of multi against single.
The multicoating on my Canon EF80mm 1.8 sucks, and in some positions, the lens flares abundantly, even with a lens hood on.
The single coatings on some of my old lenses are better than the multi of the Canon EF80mm 1.8 _________________ Lens sana in corpore sano
My Web Galleries: ORIOFOTO.NET
My Photography Blog (in Italian and English)
Read list of equipment HERE
 |
|
| Back to top |
|
 |
no-X


Joined: 19 Jul 2008 Posts: 1978 Location: Budejky, Czech Republic
|
Posted: Mon Feb 08, 2010 12:18 pm Post subject: |
|
|
I have no proof of that, but I think, that in past the optical designs were created with respect to prevent flaring - the old designers tried to avoid specific shapes of neighbouring air-glass surfaces, which could cause strong flares. Now lenses are designed by computer programs with MTF curves as priority... _________________ for sale: Vivitar (Komine) 55/2.8 Macro 1:1 (K/AR) | CZJ Tessar 13,5cm f/4.5 (M42) | Vivitar 35/1.9 (M42) | (Carl Zeiss) aus Jena 1Q Biometar z. 80/2.8 P6
list of Helios 44 lenses | List of CZJ T-marked M42 lenses | I'm not absolutely retarded, English simply isn't my mother tongue :s)
up-to 30mm: Vivitar (Tokina) Series 1 VMC 28/1.9, Vivitar (Komine) MC close-focus 28/2.8, Zeiss Distagon T* 25/2.8 ZS
35mm: Super Takumar 35/2 PRO, S-M-C Takumar 35/2, S-M-C Takumar 35/3.5, CZJ eMC Flektogon 35/2.4, SC Curtagon 35/2.8, Vivitar 35/1.9, MG Primagon V 35/4.5, CZJ Tessar T 40/4.5
50mm: S-M-C Takumar 50/1.4, S-M-C Macro Takumar 50/4, Tomioka Cosinon MC 55/1.4, Tomioka Yashinon 55/1.2, Tomioka Macro Yashinon 60/2.8, CZJ Biotar T 58/2 preset, CZJ Biotar T 58/2 17-blades, CZJ eMC Pancolar 50/1.8, aJ Pancolar 55/1.4, KMZ Helios 44-2 58/2 00xxx, KMZ Helios 44-2 58/2 0xxx, MMZ Helios MC 44-3 58/2, Helios 77M 50/1.8, KMZ Zenitar M2s MC 50/2, KMZ Industar 50/3.5, MC Volna-9 Macro 50/2.8, MC Pentacon 50/1.8, MG Trioplan 50/2.9, MG Primoplan V 58/1.9, Voigtländer Color Ultron 50/1.8, Macro Prakticar 55/2.8
85mm:, CZJ Biotar T 75/1.5 M42, CZJ eMC Pancolar 80/1.8, aJ Biometar 80/2.8 P6 zebra, CZJ Biometar 80/2.8 M42, MG Primoplan V 75/1.9 [exa], MG Night Primoplan 80/1.9 [VP Night], KMZ Helios 40-2 85/1.5 (custom hybrid of 40 and 40-2), S-M-C Takumar 85/1.8, KMZ Jupiter-9 Π 8,5/2 M39, LZOS Jupiter-9 85/2 SLR M39, LZOS Jupiter-9 85/2 M42, Kodak Meniscus 90mm, MG Telefogar V 90/3.5, MG Trioplan V 100/2.8
over 100mm: Ernemann Kinostigmat 11cm, Voigtlander SL Macro APO Lanthar 125/2.5, Spiratone 135/1.8 plura-coat, KOMZ MC Jupiter 37AM 135/3.5, KOMZ Jupiter-11 135/4, KMZ Tair 11A 135/2.8, Pentacon preset 135/2.8 (bokehmonster), CZJ Sonnar MC 135/3.5, CZJ Triotar T 135/4, LR-A Pololyt 135/4.5 "T2", ZOMZ TAIR-3 300/4.5 |
|
| Back to top |
|
 |
siriusdogstar


Joined: 05 Mar 2009 Posts: 419 Location: 40 kilometers to town
|
Posted: Mon Feb 08, 2010 3:00 pm Post subject: |
|
|
| no-X wrote: | | I have no proof of that, but I think, that in past the optical designs were created with respect to prevent flaring - the old designers tried to avoid specific shapes of neighbouring air-glass surfaces, which could cause strong flares. Now lenses are designed by computer programs with MTF curves as priority... |
sounds very reasonable to me! _________________ like attracts like! |
|
| Back to top |
|
 |
Orio

Joined: 24 Feb 2007 Posts: 18159 Location: West Emilia
|
Posted: Mon Feb 08, 2010 3:01 pm Post subject: |
|
|
| no-X wrote: | | I have no proof of that, but I think, that in past the optical designs were created with respect to prevent flaring - the old designers tried to avoid specific shapes of neighbouring air-glass surfaces, which could cause strong flares. Now lenses are designed by computer programs with MTF curves as priority... |
Flare is directly visible in the MTF. It lowers the macro contrast which is represented by the 10 lp/mm curve. _________________ Lens sana in corpore sano
My Web Galleries: ORIOFOTO.NET
My Photography Blog (in Italian and English)
Read list of equipment HERE
 |
|
| Back to top |
|
 |
kds315*


Joined: 12 Mar 2008 Posts: 2878 Location: Weinheim/Germany
|
Posted: Mon Feb 08, 2010 4:57 pm Post subject: |
|
|
| Orio wrote: | | no-X wrote: | | I have no proof of that, but I think, that in past the optical designs were created with respect to prevent flaring - the old designers tried to avoid specific shapes of neighbouring air-glass surfaces, which could cause strong flares. Now lenses are designed by computer programs with MTF curves as priority... |
Flare is directly visible in the MTF. It lowers the macro contrast which is represented by the 10 lp/mm curve. |
Only if you take real measurements as a basis! Most MTF curves shown are are simulated ones and the result of raytracing programs which do NOT consider flaring.
@peter (spotmatic): I fully agree. I have many lenses and some are so harsh and so steep in their gamma (sorry, "film speak"), that they produce burnt highlights and blacks without structure. A somewhat softer lens in that case would have allowed a camera sensor to perform better, which sometimes single coating does. Isn't it interesting that COSINA not too long ago offered lenses with multicoating and as a special order single coating? Not just coincidental I would guess... _________________ Klaus
http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary
Currently most FAV lens(es):
Nikon UV Nikkor f4.5/105mm
Voigtländer (Cosina) Apo-Makro-Lanthar f2.5 125mm SL
Want to travel to Europe and see spots hardly anyone has seen, read this:
http://www.examiner.com/x-6661-Germany-Travel-Examiner
Last edited by kds315* on Mon Feb 08, 2010 7:13 pm; edited 1 time in total |
|
| Back to top |
|
 |
Orio

Joined: 24 Feb 2007 Posts: 18159 Location: West Emilia
|
Posted: Mon Feb 08, 2010 6:12 pm Post subject: |
|
|
| kds315* wrote: | | Orio wrote: |
Flare is directly visible in the MTF. It lowers the macro contrast which is represented by the 10 lp/mm curve. |
Only if you take real measurements as a basis! Most MTF curves shown are are simulated ones and the result of raytracing programs which do NOT consider flaring. |
Yes, you're right. Useful punctualization. _________________ Lens sana in corpore sano
My Web Galleries: ORIOFOTO.NET
My Photography Blog (in Italian and English)
Read list of equipment HERE
 |
|
| Back to top |
|
 |
siriusdogstar


Joined: 05 Mar 2009 Posts: 419 Location: 40 kilometers to town
|
Posted: Mon Feb 08, 2010 7:11 pm Post subject: |
|
|
to clarify Sigma "DG" designation:
"DG Lens
The most suitable lenses for 35mm film single-lens reflex cameras, as well as for digital SLR cameras. Sigma's development of the DG (Digital) range of lenses has concentrated on the correction of distortion and aberrations. Magnification of chromatic aberration is particularly conspicuous with digital cameras. The optical designs and cutting-edge technology incorporated by Sigma eliminate flare and ghosting from te image sensor and create excellent color balance. Vignetting is minimized whilst marginal illumination is ensured. These high performance lenses are equally suited for digital and analogue cameras."
ref: http://www.sigmaphoto.com/lenses/lenses.asp (scroll down) _________________ like attracts like! |
|
| Back to top |
|
 |
dnas

Joined: 14 Nov 2008 Posts: 139 Location: Japan
|
Posted: Tue Feb 16, 2010 12:14 am Post subject: |
|
|
| cooltouch wrote: | For instance, it has been pretty well documented that the Tamron SP 90mm f/2.5 Macro (models 52B and 52BB) causes a hot spot to appear in the center of the image with many DSLRs. I have confirmed this with my own Tamron 52B and my Canon XS. But in the case of my lens and camera, this hot spot is a rather minor one, only beginning to show once I've stopped the lens down to about f/8 or so. So, as long as I shoot with the lens fairly wide open, I'm okay.
Now the reason that has been cited for this problem with the Tamron is it has a flat rear element, which is the culprit. |
Here are some test shots that I took which shows the hotspot on the Tamron SP 90mm F2.5.
At F32:
At F16:
At F11:
Although you can no longer see the spot at apertures larger than around F5.6 because the "spot" gets larger than the whole frame, the fact that the spot is still there, means the shot will be less contrasty because of the reflection off the flat rear element. |
|
| Back to top |
|
 |
kds315*


Joined: 12 Mar 2008 Posts: 2878 Location: Weinheim/Germany
|
|
| Back to top |
|
 |
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|