Concerning the Coastal Optics 60mm f/4 UV-VIS-IR APO macro

[michael_oxford]

<p>I have a friend that is a Canon shooter and also the most demanding person of optics I know (he actually got me into APO refractors and such). He has been dissatisfied with all Canon standard lens offering and recently showed interest in the Coastal Optics 60mm APO for use as a normal lens on his EOS 1d MkIII. I told him I'd post up a question here on P.Net so he could maybe hear from people with real world experience with the lens.</p>

<p>I know that Bjorn Rorslett said this about the 60mm in another recent thread:</p>

<blockquote>

 

<p>This lens has tremendous sharpness, is truly apochromatic and so well corrected that there never is any of the colour fringing than one might observe with other lenses (including the 50 AFS, by the way). Geometric distortion is virtually non-existent too. Sharpness peaks by design at f/5.6 so the 60 APO should be precisely what Ellis is looking for (except for the price tag which is of the stiffer kind). I always have a sample of it with me for field work, even on occasions where no UV or IR is planned.<br>

A marvellous lens if you can afford it.</p>

 

 

</blockquote>

<p>With all respect to Bjorn, can anyone else back this up? Also would it really be viable as a standard lens considering it has to be mounted with an adapter and stopped down metering must be used?</p>

<p>Thanks in advance,<br>

Mike</p>

<p><a href="../photodb/user?user_id=79334"><br /> </a></p>

[oskar_ojala]

<p>Coincidentally, I just finished reading this: http://diglloyd.com/diglloyd/free/CoastalOptics60f4/index.html<br>

Of course if your friend is both loaded and dissatisfied, he could switch to medium format to get higher image quality.</p>

[waldemar_giers___kitchener]

<p>Bjorn knows what he's saying. Besides obvious quality of Coastal Optics 60mm lens lays financial part of it. At almost $5000 someone need to ask yourself question - Is masculine improvement in quality worth it? Especially if he plans to use it as regular glass, not multispectrum tool. Some of Zeiss offering may work as good at fraction of final price.</p><div></div>

[jose_angel]

<p>A $5000 f4 "standard" lens, manual focus, to be used via adapter, only stop down metering for "normal" use on a digital camera?<br />Not for me. For sure a wonderful lens, but my "family pics" can stand with the current Nikon offer. I think it`s another lens for "true" professional use.</p>

[walterh]

<p>I think it is a special lens for special applications. Unless you have this special application I would advice to get a D3x and use a Zeiss 50mm or 100mm macro lens :-) You can still claim that you spend a lot of money :-P</p>

[bjørn rørslett]

<p>All I can say is that quality and price coincide for this lens. Of course it's a pure waste of money to buy it just because one can afford the purchase. You need to have a well-founded reason for doing so.</p>

<p>It's one of my top favourites for my "F" mount cameras.</p>

[iliafarniev]

<p>Basically, I would agree with Walter Schroeder, the Zeiss products he mention will cover very well for exidingly creative cravings of every kind. BTW, purely by chance I have made few shots looking surprizinglly similar to one above shooting Kodak Elitechrome 400 thorough CZJ Tessar 2.8/50mm edition year 1985 last summer. Looks kind of strange and interesting first but you probably can't sell many of them. Even current Canon 100mm macro is good for almost anything imaginable on short range. Not to mention PP arts. Zeiss 2,8/50macro is very good thorough whole range at 4.o to 11.0, shots look unique and classy and not too far away from main stream editorial testes. IMO if you don't have a clients to pay $375 for a scientifically correct shot every time, better save money.</p>

[michael_oxford]

<p>I don't think a lot of you get it. It's not about saying "I have a $4500 lens." It's about the "scientifically correct" part, and the results that come with it. I thought most P.Net users would be more discriminating than this. </p>

[johnw63]

<p>I think they ARE discriminating. Most seem to feel the gain is not worth the cost. Most don't NEED to be scientifically as perfect as money can buy. Bjorn seems to have found a need and a reason to spend the money.</p>

[bjørn rørslett]

<p>I obtained the CoastalOpt 60 mainly for shooting UV, IR, and multispectral composites with it. My UV-Nikkors do well with UV of course, but unlike the Coastal these lenses are not parfocal over the entire spectral range transmitted so making multispectral images is a hassle. Also, getting critical IR focus is not that easy with the UV-Nikkor. Plus for some subjects, the 105mm focal length can be on the longer side because most of my UV and IR work is conducted with DX-format cameras. Using the CoastalOpt 60 APO circumvents all these issues with ease since visible focus matches UV or IR focus perfectly.</p>

<p>Later I discovered that the 60 APO also serves as a wonderful normal lens for visible light work. So it has seen considerable use on the D3 and D3X bodies too.</p>

[oskar_ojala]

<p>I think people do get it; why spend the money on such a lens and then don't do work outside the visible spectrum with it? As mentioned, there are other superb lenses available and there are larger formats available if more resolution is craved for.</p>

[tommyinca]

<p>Ah, we need (other) folks to spend money now. Please buy :-)</p>

[michael_oxford]

<blockquote>

<p>I thought most P.Net users would be more discriminating than this.</p>

 

</blockquote>

<p>Please excuse this statement - It came off the wrong way and I apologize. Not much else needs to be said on the subject. I think my disappointemt in the responses is due to the fact that I was not all that descriptive in the OP.</p>

<p>Anyway, the person that would be using this is a observatory director/semi pro photographer by trade, so while he would use it mainly for visible light applications, he would absolutley take advantage of UV/IR capabilities for scientific/astronomy applications. And if it is truly apochromatic across the whole range, even better. - He has disregarded the Zeiss lenses because apparently there is a Japanese astronomy magazine that tested them and said they weren't too hot. Misaligned elements and such.<br>

So my next question about it becomes "how is the corner sharpness/distortion control? coma?"</p>

 

[bjørn rørslett]

<p>The lens is extremely well corrected, if that's what you're asking about. Each sample is assembled by hand - this is not a mass production item.</p>

<p>I believe the CoastalOpt site has a pdf for download with all the details, down to MTF curves and graphs showing performance in various spectral bands. You could always ask the Coastal guys for these details if their site doesn't provide enough information, I'm certain they're just pleased to help you. Or contact the designer, Dr. Brian Caldwell, who is a member of the photo.net community.</p>

[p_mui]

<p>Gentlemen -<br>

Here are the things I'm looking for.<br>

1. Strehl ratio numbers.<br>

2. An interferometer and total fringe report.<br>

3. An optic that will generate PERFECT, or close to accurate pinpoints for point sources. <br>

4. A FLAT field with very little curvature.<br>

5. Image circle numbers.<br>

6. Method of manufacture, that is, do they compensate for the melt data of each type of glass and crystalline or do they rely solely on the melt data that the manufacturer provides them?<br>

7. Method of polish for the lenses. Are they high speed polyurethane or pitch polished?<br>

8. Are the batches of lenses consistent from one to another in terms of color correction, figure, etc?<br>

9. Are the retaining rings "trimmed" in any way for critical alignment?<br>

The optic will be used for astronomy purposes with an SBIG (santa barbara instruments group) camera that has a KAF3200ME full frame chip. The optic that I'm looking for MUST render star points as accurately as possible for photometry and imaging. Also the optic will be adapted to larger imagers (STL11000 and larger interline and full frame sensors). <br>

I have tried MANY other brands that are commercially available with great disappointment. This includes Nikon, Canon, etc. All of them are considered "top rated" but none of them have accurately (color correction and pin point wise) have even been close to satisfactory. <br>

The "standard" of performance that I'm looking for would have to EQUAL or BEAT out a precision telescope from Telescope Engineering Company, Astro Physics or the high end Takahashi offerings. Not in terms of focal length, mind you, but in terms of color correction, flatness of field and rendition of point sources.<br>

There have been several reviews of optics that were highly rated in terrestrial usage but they have been lacking in accuracy of point sources as well as color correction.<br>

If anyone has any REAL numbers other than those provided by the datasheet, the info would be greatly appreciated. This also applies to the method of testing and manufacture of the lens.<br>

An optic with a 1/50th rms wavefront would be a good start. Or a 1/10th PV.</p>

 

[michael_oxford]

<p>Jeez, Mr. Mui, maybe you should have just given me some more specific information about what you wanted me to ask before I naievly post a someting stupidly vauge on P.Net!</p>

[brian_caldwell]

<p><em>

<p>P Mui: <br>

1. Strehl ratio numbers.</p>

</em><br>

For an aperture of f/4: Strehl >0.8 (~Rayleigh limit) from ~480nm to ~800nm with peaks of 0.25, 0.995, and 0.955 at 320nm, 520nm, and 770nm, respectively. The Strehl ratio is very nonlinear with respect to defocus - a defocus of only a few microns will have a noticeable impact on the Strehl ratio at f/4. At f/8 the Strehl ratio is greater than 0.8 over the entire waveband from 315nm to 1100nm.<br>

<br /><em>2. An interferometer and total fringe report.</em>

<p>I prefer projection testing for wide field broadband optics. Coastal could do on-axis interferometry at 6328nm for an extra fee. Accurate off-axis testing referenced to a true flat field would require complex fixturing and significantly greater cost. Multiple wavelength interferometry is not currently practical.<br>

<br /><em>3. An optic that will generate PERFECT, or close to accurate pinpoints for point sources. </em>

<p>Relative aperture matters here. Typical high-end apo refractors are slow at ~ f/8. If you are satisfied with these refractors then you should be satisfied with point images equal or smaller than diffraction-limited f/8 point images. Wide open at f/4, the 60 Apo satisfies this condition near the axis, and nearly satisfies this condition in the corners of your 3200 chip. One stop down at f/5.6 the condition is satisfied over the full 3200 format. Two stops down at f/8 the condition is satisfied over a full FX format.<br>

<br /><em>4. A FLAT field with very little curvature.</em>

<p>Comments above and all MTF curves shown in the online brochure pertain to a perfectly flat image field.<br>

<br /><em>5. Image circle numbers.</em>

<p>See 3 above or the published MTF data.<br>

<br /><em>6. Method of manufacture, that is, do they compensate for the melt data of each type of glass and crystalline or do they rely solely on the melt data that the manufacturer provides them?</em>

<p>No. Not practical due to extreme cost (would require custom glass measurements outside the visible band), and not needed since most of the optical elements are chemically pure substances (CaF2 or SiO2)<br>

<br /><em>7. Method of polish for the lenses. Are they high speed polyurethane or pitch polished?</em>

<p>No high speed polishing.<br>

<br /><em>8. Are the batches of lenses consistent from one to another in terms of color correction, figure, etc?</em>

<p>Yes.<br>

<br /><em>9. Are the retaining rings "trimmed" in any way for critical alignment?</em>

<p>Air space adjustment not needed due to tolerant design (unlike air-spaced APO refractors). Lateral compensators are used to adjust off-axis performance.<br>

<br /><em>The optic will be used for astronomy purposes with an SBIG (santa barbara instruments group) camera that has a KAF3200ME full frame chip. The optic that I'm looking for MUST render star points as accurately as possible for photometry and imaging. Also the optic will be adapted to larger imagers (STL11000 and larger interline and full frame sensors). </em>

<p>60 APO will work very well on KAF3200, even wide open. For STL1100 you may want to stop down to f/8 to achieve optimum corner performance.<br>

<br /><em>I have tried MANY other brands that are commercially available with great disappointment. This includes Nikon, Canon, etc. All of them are considered "top rated" but none of them have accurately (color correction and pin point wise) have even been close to satisfactory. </em>

<p>Which ones? What aperture?<br>

<br /><em>The "standard" of performance that I'm looking for would have to EQUAL or BEAT out a precision telescope from Telescope Engineering Company, Astro Physics or the high end Takahashi offerings. Not in terms of focal length, mind you, but in terms of color correction, flatness of field and rendition of point sources.</em>

<p>This is a reasonable standard, but see my comments about relative aperture in part 3 above.<br>

<br /><em>There have been several reviews of optics that were highly rated in terrestrial usage but they have been lacking in accuracy of point sources as well as color correction.<br />If anyone has any REAL numbers other than those provided by the datasheet, the info would be greatly appreciated. This also applies to the method of testing and manufacture of the lens.<br />An optic with a 1/50th rms wavefront would be a good start. Or a 1/10th PV.</em>

<p>Are you *sure* you are getting this with above-mentioned telescopes over a broad waveband? Of course, relative aperture is critically important for a wavefront error criterion. It is possible to build a 60mm lens covering 24x36mm at ~f/2 (or maybe even faster) that has smaller point images than any of the telescopes you mention. Email me if you are interested.</p>

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[p_mui]

<p>Brian,<br>

Thanks for getting back to me. The lenses that I've tried were the Canon 800 f/5.6L EF IS, Canon 300 2.8L EF (both IS and NON IS models), Canon 600 4 EF L IS, Canon 400 2.8L EF IS, Canon 200 1.8L EF, Canon 85 1.2L EF II and I models, Nikon 300 2.8 VR, Nikon 70-200 2.8 VR - the list goes on and on. While many of the people will be happy with the lenses listed above, I actually use a Takahashi FSQ106N, Takahashi FS152, Astro Physics 130EDT, Astro Physics 155EDFS and other refractors for imaging. I find that the FSQ106N has outstanding color correction and contrast when compared to the "standard" autofocus lenses currently on the market. <br>

The Canon 800 (as well as most standard terrestrial lenses) have been a disappointment. There is quite a bit of flaring when shooting high contrast objects. For example a white Egret against a dark background. The egret will have a "bloom" to it and stopping down does not help matters any. I have tried many samples of the 800 and have been disappointed. I try the same scene with the Takahashi FSQ106N and the results are outstanding. Both of these I would set on manual focus using 10x on the Liveview option.<br>

On astronomy imaging, the limitations of the Canon/Nikon/Zeiss,etc lenses just becomes much more pronounced. I'm looking for pinpoint images, wide open, or even stopped down 1 stop. The Tak FSQ106N - pinpoints on a 20x30 enlargement with a STL11000, and some of the stars are still smaller than a pinpoint (literally) but are easily resolved. <br>

Some of the astro imaging tests done by other photographers can be seen here.<br>

http://www.astropix.com/HTML/I_ASTROP/EQ_TESTS/C300MM.HTM<br>

http://www.astropix.com/HTML/I_ASTROP/EQ_TESTS/N400MM.HTM<br>

As for the PV numbers, Roland at Astro Physics will always attest to his telescopes. Many of the 130/6.3 and the older 130/6 models are testing at better than .95 strehl. I have seen .995 and better from the batches, the .95 is probably the lowest number that I've seen. http://www.astro-physics.com<br>

Color correction - I routinely use the Takahashi FSQ106N for terrestrial photography since it doesn't have the "warmish" character of the Canon lenses, nor the "cold" character of the german glass. To me, the FSQ106N is quite neutral and I've already recommended this lens to Jonathon Singer who will give it a spin with his Hasselblad 39 megapixel and 50+ megapixel backs. For those that know Jonathon, he demands absolute color fidelity without any "character" imposed. I'm very sure he'll be pleased with the Takahashi. http://www.botanicamagnifica.com/<br>

I'm one of the few that will use a high end refractor for terrestrial photography. Nature Photographer featured my article on this - you can find it in the winter 2008 issue. It's quite possibly the FIRST international publication (non web) in a non astronomy related magazine. Other photographers are adopting to this method also mainly due to cost and better optical quality at equivalent f/ratios and f/lengths.<br>

How much more would the lens report add to the cost?</p>