FLT没有后组镜片, 像场平坦度的确不能和FSQ比, 这也是我现在更换为FSQ的原因, FSQ可以说是一个极致的快速"广角"摄星镜, FLT/TMB大概只偏向于观测. FSQ很棒！！ 后组镜片,的作用很大，那个pentax 75SDHF也用了一片后租镜片，结果像场大到67都能用。 我觉得不必过分关注它是否是萤石，关键看性能，如果我没记错的AP 105也不是萤石，性能却不也不输FSQ。 agong那三张照片是直焦拍的吧！原来看过一些资料，发现TMB的边缘像质不甚理想，个人一直认为是目镜畸变造成，这次终于证实TMB在边缘像质控制与高桥相差甚远！ 现在的主要目的是想搞清楚这个问题吧， 的确不是非萤石不可。 我已去信景德。
也不能这么说
最初由 lxyfuzz 发表agong那三张照片是直焦拍的吧！原来看过一些资料，发现TMB的边缘像质不甚理想，个人一直认为是目镜畸变造成，这次终于证实TMB在边缘像质控制与高桥相差甚远！
FSQ-106后置那一片实际上可以认为是平象镜，如果TMB105也加配上平象镜的话，应该不会差到哪里去。不过TMB的平象镜可不便宜，据说至少6K人民币。 我所说的不单是高桥的FSQ-106的边缘校正比TMB强，高桥的其他镜子在这方面似乎都比TMB好，TMB最致命的弱点就是边缘不好，是不是为了中心最优像质牺牲了边缘呢？ 后组镜片起的就是平整像场作用。 FSQ106可以说是高桥的一个特殊的折射镜， 其设计是针对大像场拍摄， 所以加入了后组的像场修正镜， 所以它实际更多的被称为“摄星镜”。 而TMB105可以说做出来就不是这个目的。 但它的确也有专用的修正镜， 据说装上后完全可用于6X7的摄影， 不过我没见识过。
我觉得在像场上应该拿来和TMB105比较的是那些没有后组镜片的顶级10厘米折射镜， 可惜没有这个条件。
现在市面上带后组镜片的折射镜好像并不多？ 感觉主要是日本厂家喜欢推出这种镜子， 比如高桥、PENTAX、VIXEN等（特别是PENTAX， 好几个型号都有后组镜片）。 TMB的边缘尽管没有跟其他没后组的镜子比较过， 但个人感觉是有点差。
最初由 lxyfuzz 发表
我所说的不单是高桥的FSQ-106的边缘校正比TMB强，高桥的其他镜子在这方面似乎都比TMB好，TMB最致命的弱点就是边缘不好，是不是为了中心最优像质牺牲了边缘呢？ 唉！可惜我这里没有单反，好镜子到是有一支！ 其他镜子不知道，FS-60C的边缘也很差，不加减焦镜几乎不能做摄影，所以我觉得TMB的边缘应算正常，不能说特别差。不过，还是希望真正专家来说说吧，我也是门外汉，说话不算数。 这里有一段cloudynights上对TMB105的评论， 我摘录一点他的总结， 里面提到了几个镜子及TMB的像场， 全文大家可以自己去看看。
http://www.cloudynights.com/reviews/tmb105.htm
I wrote this review to express my "consumer" impressions and opinions. Clearly, the TMB triplets show state-of-the-art optical design and display a level of workmanship that challenges or exceeds the competition. Even though I used the TMB alongside several other refractors and reflectors, I will leave the task of exhaustive direct comparison to others. I saw pleasing optical performance in the TMB that I have not seen in the competitor products, which led me to believe that I had made the right choice.
All things considered, I would say that the AP scopes have met their match, and I would bet that half of the upcoming direct comparison reviews will favor the TMB. The Taks (102's, etc) have been easily surpassed in color correction (in all fairness, the FSQ-106 is an astrograph, not a fast APO), and the TV-101 continues to be surpassed on all counts by the TMB. Having said that, I believe that the owners of TeleVue 101's will find the view a little different. Once you are accustomed to the edge-to-edge flat field of the 101's flat-field Petzval design, the curved field of a fast triplet refractor may take some getting used to. However, the TMB's gain in contrast, sharpness, and planetary performance is quite noticeable to me, as compared to the TV-101. It all boils down to your preferences and priorities. Personally, I traded the flat field of the TV for the portability and optical rigor of the TMB. TV101的设计似乎和FSQ106一样？ 对了，我的问题你还没回答，再问一次，电动对焦在FLT也不能用吗？ 哦， 抱歉。 在FLT当然能用， 可惜我要跟FLT告别了。 景德公司的老板杨德良先生已经给了我回答， 的确不是萤石而是SD的， 以下是他的详细解释：
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Dear Mr. Gong,
Thank you for your question, your English is better than me.
Your FLT 105 is using Russian SD( 95% same as fluorite) the color correction is same as fluorite but the sharpness is 10-20% better than FSQ 106 in high power.
please check it by using high power eyepiece tonight.
I owned a FSQ before, we have compared more than 10 time in the past 3 years, most people like FLT 105 better than FSQ 106 in star observation.
FSQ is good in photography purpose.
Best Regards,
William Yang
William Optics USA
www.william-optics.com
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以前是我没搞清楚就随口说了， 对此先向各位抱歉， 我会马上更正此问题。 景德的镜子很有意思.80的APO用的是三片中间一片萤石而没用类似FLT105的SD结构.
80用SD结构做成APO效果肯定也差不了.价格是否便宜很多呢